Index: /trunk/src/VBox/ValidationKit/bootsectors/Makefile.kmk
===================================================================
--- /trunk/src/VBox/ValidationKit/bootsectors/Makefile.kmk	(revision 60749)
+++ /trunk/src/VBox/ValidationKit/bootsectors/Makefile.kmk	(revision 60750)
@@ -240,4 +240,5 @@
 	bs3kit/bs3-first-rm.asm \
 	bs3-cpu-basic-2.c \
+	bs3-cpu-basic-2-x0.c \
 	bs3-cpu-basic-2-asm.asm \
        bs3kit/bs3-cmn-instantiate-x0.c16 \
Index: /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-template.c
===================================================================
--- /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-template.c	(revision 60749)
+++ /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-template.c	(revision 60750)
@@ -44,11 +44,4 @@
     } while (0)
 
-
-#ifdef BS3_INSTANTIATING_CMN
-/** Indicating that we've got operand size prefix and that it matters. */
-# define BS3CB2SIDTSGDT_F_OPSIZE    UINT8_C(0x01)
-/** Worker requires 386 or later. */
-# define BS3CB2SIDTSGDT_F_386PLUS   UINT8_C(0x02)
-#endif
 
 #ifdef BS3_INSTANTIATING_MODE
@@ -91,14 +84,4 @@
     uint8_t u1DescType;
 } BS3CB2INVLDESCTYPE;
-
-typedef struct BS3CB2SIDTSGDT
-{
-    const char *pszDesc;
-    FPFNBS3FAR  fpfnWorker;
-    uint8_t     cbInstr;
-    bool        fSs;
-    uint8_t     bMode;
-    uint8_t     fFlags;
-} BS3CB2SIDTSGDT;
 #endif
 
@@ -115,58 +98,4 @@
 # define            g_bs3CpuBasic2_ud2_FlatAddr BS3_DATA_NM(g_bs3CpuBasic2_ud2_FlatAddr)
 extern uint32_t     g_bs3CpuBasic2_ud2_FlatAddr;
-
-extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sidt_ss_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sidt_ss_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sidt_rexw_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_rexw_bx_ud2_c64;
-
-extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_ss_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_ss_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_rexw_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_rexw_bx_ud2_c64;
-
-extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lidt_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt32_es_di__lidt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64;
-
-extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
-extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
-
 #endif
 
@@ -182,75 +111,4 @@
 # define                    g_f16BitSys     BS3_CMN_NM(g_f16BitSys)
 static bool                 g_f16BitSys = 1;
-
-
-/** SIDT test workers. */
-static BS3CB2SIDTSGDT const g_aSidtWorkers[] =
-{
-    { "", bs3CpuBasic2_sidt_bx_ud2_c16,             3, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "", bs3CpuBasic2_sidt_ss_bx_ud2_c16,          4, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "", bs3CpuBasic2_sidt_opsize_bx_ud2_c16,      4, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
-    { "", bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c16,   5, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
-    { "", bs3CpuBasic2_sidt_bx_ud2_c32,             3, false,   BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sidt_ss_bx_ud2_c32,          4, true,    BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sidt_opsize_bx_ud2_c32,      4, false,   BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c32,   5, true,    BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sidt_bx_ud2_c64,             3, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sidt_rexw_bx_ud2_c64,        4, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sidt_opsize_bx_ud2_c64,      4, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sidt_opsize_rexw_bx_ud2_c64, 5, false,   BS3_MODE_CODE_64, 0 },
-};
-
-/** SGDT test workers. */
-static BS3CB2SIDTSGDT const g_aSgdtWorkers[] =
-{
-    { "", bs3CpuBasic2_sgdt_bx_ud2_c16,             3, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "", bs3CpuBasic2_sgdt_ss_bx_ud2_c16,          4, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "", bs3CpuBasic2_sgdt_opsize_bx_ud2_c16,      4, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
-    { "", bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c16,   5, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
-    { "", bs3CpuBasic2_sgdt_bx_ud2_c32,             3, false,   BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sgdt_ss_bx_ud2_c32,          4, true,    BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sgdt_opsize_bx_ud2_c32,      4, false,   BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c32,   5, true,    BS3_MODE_CODE_32, 0 },
-    { "", bs3CpuBasic2_sgdt_bx_ud2_c64,             3, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sgdt_rexw_bx_ud2_c64,        4, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sgdt_opsize_bx_ud2_c64,      4, false,   BS3_MODE_CODE_64, 0 },
-    { "", bs3CpuBasic2_sgdt_opsize_rexw_bx_ud2_c64, 5, false,   BS3_MODE_CODE_64, 0 },
-};
-
-/** LIDT test workers. */
-static BS3CB2SIDTSGDT const g_aLidtWorkers[] =
-{
-    { "lidt [bx]",              bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c16,             11, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "lidt [ss:bx]",           bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c16,          12, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "o32 lidt [bx]",          bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c16,      12, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
-    { "o32 lidt [bx]; sidt32",  bs3CpuBasic2_lidt_opsize_bx__sidt32_es_di__lidt_es_si__ud2_c16,    27, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
-    { "o32 lidt [ss:bx]",       bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c16,   13, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
-    { "lidt [ebx]",             bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c32,             11, false,   BS3_MODE_CODE_32, 0 },
-    { "lidt [ss:ebx]",          bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c32,          12, true,    BS3_MODE_CODE_32, 0 },
-    { "o16 lidt [ebx]",         bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c32,      12, false,   BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
-    { "o16 lidt [ss:ebx]",      bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c32,   13, true,    BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
-    { "lidt [rbx]",             bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c64,              9, false,   BS3_MODE_CODE_64, 0 },
-    { "o64 lidt [rbx]",         bs3CpuBasic2_lidt_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64,        10, false,   BS3_MODE_CODE_64, 0 },
-    { "o32 lidt [rbx]",         bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c64,      10, false,   BS3_MODE_CODE_64, 0 },
-    { "o32 o64 lidt [rbx]",     bs3CpuBasic2_lidt_opsize_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64, 11, false,   BS3_MODE_CODE_64, 0 },
-};
-
-/** LGDT test workers. */
-static BS3CB2SIDTSGDT const g_aLgdtWorkers[] =
-{
-    { "lgdt [bx]",              bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c16,             11, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "lgdt [ss:bx]",           bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16,          12, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
-    { "o32 lgdt [bx]",          bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c16,      12, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
-    { "o32 lgdt [ss:bx]",       bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16,   13, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
-    { "lgdt [ebx]",             bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c32,             11, false,   BS3_MODE_CODE_32, 0 },
-    { "lgdt [ss:ebx]",          bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32,          12, true,    BS3_MODE_CODE_32, 0 },
-    { "o16 lgdt [ebx]",         bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c32,      12, false,   BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
-    { "o16 lgdt [ss:ebx]",      bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32,   13, true,    BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
-    { "lgdt [rbx]",             bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c64,              9, false,   BS3_MODE_CODE_64, 0 },
-    { "o64 lgdt [rbx]",         bs3CpuBasic2_lgdt_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64,        10, false,   BS3_MODE_CODE_64, 0 },
-    { "o32 lgdt [rbx]",         bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c64,      10, false,   BS3_MODE_CODE_64, 0 },
-    { "o32 o64 lgdt [rbx]",     bs3CpuBasic2_lgdt_opsize_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64, 11, false,   BS3_MODE_CODE_64, 0 },
-};
-
 
 
@@ -1445,1466 +1303,4 @@
 }
 
-#if TMPL_BITS == 16
-
-/**
- * Executes one round of SIDT and SGDT tests using one assembly worker.
- *
- * This is written with driving everything from the 16-bit or 32-bit worker in
- * mind, i.e. not assuming the test bitcount is the same as the current.
- */
-# define bs3CpuBasic2_sidt_sgdt_One BS3_CMN_NM(bs3CpuBasic2_sidt_sgdt_One)
-BS3_DECL_NEAR(void) bs3CpuBasic2_sidt_sgdt_One(BS3CB2SIDTSGDT const BS3_FAR *pWorker, uint8_t bTestMode, uint8_t bRing,
-                                               uint8_t const *pbExpected)
-{
-    BS3TRAPFRAME        TrapCtx;
-    BS3REGCTX           Ctx;
-    BS3REGCTX           CtxUdExpected;
-    BS3REGCTX           TmpCtx;
-    uint8_t const       cbBuf = 8*2;         /* test buffer area  */
-    uint8_t             abBuf[8*2 + 8 + 8];  /* test buffer w/ misalignment test space and some extra guard. */
-    uint8_t BS3_FAR    *pbBuf  = abBuf;
-    uint8_t const       cbIdtr = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 2+8 : 2+4;
-    bool const          f286   = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80286;
-    uint8_t             bFiller;
-    int                 off;
-    int                 off2;
-    unsigned            cb;
-    uint8_t BS3_FAR    *pbTest;
-
-    /* make sure they're allocated  */
-    Bs3MemZero(&Ctx, sizeof(Ctx));
-    Bs3MemZero(&CtxUdExpected, sizeof(CtxUdExpected));
-    Bs3MemZero(&TmpCtx, sizeof(TmpCtx));
-    Bs3MemZero(&TrapCtx, sizeof(TrapCtx));
-    Bs3MemZero(&abBuf, sizeof(abBuf));
-
-    /* Create a context, give this routine some more stack space, point the context
-       at our SIDT [xBX] + UD2 combo, and point DS:xBX at abBuf. */
-    Bs3RegCtxSaveEx(&Ctx, bTestMode, 256 /*cbExtraStack*/);
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
-    Bs3RegCtxSetRipCsFromLnkPtr(&Ctx, pWorker->fpfnWorker);
-    if (BS3_MODE_IS_16BIT_SYS(bTestMode))
-        g_uBs3TrapEipHint = Ctx.rip.u32;
-    if (!BS3_MODE_IS_RM_OR_V86(bTestMode))
-        Bs3RegCtxConvertToRingX(&Ctx, bRing);
-
-    /* For successful SIDT attempts, we'll stop at the UD2. */
-    Bs3MemCpy(&CtxUdExpected, &Ctx, sizeof(Ctx));
-    CtxUdExpected.rip.u += pWorker->cbInstr;
-
-    /*
-     * Check that it works at all and that only bytes we expect gets written to.
-     */
-    /* First with zero buffer. */
-    Bs3MemZero(abBuf, sizeof(abBuf));
-    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), 0))
-        Bs3TestFailedF("ASMMemIsAllU8 or Bs3MemZero is busted: abBuf=%.*Rhxs\n", sizeof(abBuf), pbBuf);
-    if (!ASMMemIsZero(abBuf, sizeof(abBuf)))
-        Bs3TestFailedF("ASMMemIsZero or Bs3MemZero is busted: abBuf=%.*Rhxs\n", sizeof(abBuf), pbBuf);
-    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-    if (f286 && abBuf[cbIdtr - 1] != 0xff)
-        Bs3TestFailedF("286: Top base byte isn't 0xff (#1): %#x\n", abBuf[cbIdtr - 1]);
-    if (!ASMMemIsZero(&abBuf[cbIdtr], cbBuf - cbIdtr))
-        Bs3TestFailedF("Unexpected buffer bytes set (#1): cbIdtr=%u abBuf=%.*Rhxs\n", cbIdtr, cbBuf, pbBuf);
-    if (Bs3MemCmp(abBuf, pbExpected, cbIdtr) != 0)
-        Bs3TestFailedF("Mismatch (#1): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, abBuf);
-    g_usBs3TestStep++;
-
-    /* Again with a buffer filled with a byte not occuring in the previous result. */
-    bFiller = 0x55;
-    while (Bs3MemChr(abBuf, bFiller, cbBuf) != NULL)
-        bFiller++;
-    Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
-    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
-        Bs3TestFailedF("ASMMemIsAllU8 or Bs3MemSet is busted: bFiller=%#x abBuf=%.*Rhxs\n", bFiller, sizeof(abBuf), pbBuf);
-
-    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-    if (f286 && abBuf[cbIdtr - 1] != 0xff)
-        Bs3TestFailedF("286: Top base byte isn't 0xff (#2): %#x\n", abBuf[cbIdtr - 1]);
-    if (!ASMMemIsAllU8(&abBuf[cbIdtr], cbBuf - cbIdtr, bFiller))
-        Bs3TestFailedF("Unexpected buffer bytes set (#2): cbIdtr=%u bFiller=%#x abBuf=%.*Rhxs\n", cbIdtr, bFiller, cbBuf, pbBuf);
-    if (Bs3MemChr(abBuf, bFiller, cbIdtr) != NULL)
-        Bs3TestFailedF("Not all bytes touched: cbIdtr=%u bFiller=%#x abBuf=%.*Rhxs\n", cbIdtr, bFiller, cbBuf, pbBuf);
-    if (Bs3MemCmp(abBuf, pbExpected, cbIdtr) != 0)
-        Bs3TestFailedF("Mismatch (#2): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, abBuf);
-    g_usBs3TestStep++;
-
-    /*
-     * Slide the buffer along 8 bytes to cover misalignment.
-     */
-    for (off = 0; off < 8; off++)
-    {
-        pbBuf = &abBuf[off];
-        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &abBuf[off]);
-        CtxUdExpected.rbx.u = Ctx.rbx.u;
-
-        /* First with zero buffer. */
-        Bs3MemZero(abBuf, sizeof(abBuf));
-        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-        if (off > 0 && !ASMMemIsZero(abBuf, off))
-            Bs3TestFailedF("Unexpected buffer bytes set before (#3): cbIdtr=%u off=%u abBuf=%.*Rhxs\n",
-                           cbIdtr, off, off + cbBuf, abBuf);
-        if (!ASMMemIsZero(&abBuf[off + cbIdtr], sizeof(abBuf) - cbIdtr - off))
-            Bs3TestFailedF("Unexpected buffer bytes set after (#3): cbIdtr=%u off=%u abBuf=%.*Rhxs\n",
-                           cbIdtr, off, off + cbBuf, abBuf);
-        if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
-            Bs3TestFailedF("286: Top base byte isn't 0xff (#3): %#x\n", abBuf[off + cbIdtr - 1]);
-        if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
-            Bs3TestFailedF("Mismatch (#3): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
-        g_usBs3TestStep++;
-
-        /* Again with a buffer filled with a byte not occuring in the previous result. */
-        Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
-        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-        if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
-            Bs3TestFailedF("Unexpected buffer bytes set before (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
-        if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - cbIdtr - off, bFiller))
-            Bs3TestFailedF("Unexpected buffer bytes set after (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
-        if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
-            Bs3TestFailedF("Not all bytes touched (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
-        if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
-            Bs3TestFailedF("286: Top base byte isn't 0xff (#4): %#x\n", abBuf[off + cbIdtr - 1]);
-        if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
-            Bs3TestFailedF("Mismatch (#4): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
-        g_usBs3TestStep++;
-    }
-    pbBuf = abBuf;
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
-    CtxUdExpected.rbx.u = Ctx.rbx.u;
-
-    /*
-     * Play with the selector limit if the target mode supports limit checking
-     * We use BS3_SEL_TEST_PAGE_00 for this
-     */
-    if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
-        && !BS3_MODE_IS_64BIT_CODE(bTestMode))
-    {
-        uint16_t cbLimit;
-        uint32_t uFlatBuf = Bs3SelPtrToFlat(abBuf);
-        Bs3GdteTestPage00 = Bs3Gdte_DATA16;
-        Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
-        Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatBuf;
-        Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatBuf >> 16);
-        Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatBuf >> 24);
-
-        if (pWorker->fSs)
-            CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
-        else
-            CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-
-        /* Expand up (normal). */
-        for (off = 0; off < 8; off++)
-        {
-            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
-            {
-                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (off + cbIdtr <= cbLimit + 1)
-                {
-                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                    if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
-                        Bs3TestFailedF("Not all bytes touched (#5): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                    if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
-                        Bs3TestFailedF("Mismatch (#5): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
-                    if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
-                        Bs3TestFailedF("286: Top base byte isn't 0xff (#5): %#x\n", abBuf[off + cbIdtr - 1]);
-                }
-                else
-                {
-                    if (pWorker->fSs)
-                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                    else
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                    if (off + 2 <= cbLimit + 1)
-                    {
-                        if (Bs3MemChr(&abBuf[off], bFiller, 2) != NULL)
-                            Bs3TestFailedF("Limit bytes not touched (#6): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                           cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                        if (Bs3MemCmp(&abBuf[off], pbExpected, 2) != 0)
-                            Bs3TestFailedF("Mismatch (#6): expected %.2Rhxs, got %.2Rhxs\n", pbExpected, &abBuf[off]);
-                        if (!ASMMemIsAllU8(&abBuf[off + 2], cbIdtr - 2, bFiller))
-                            Bs3TestFailedF("Base bytes touched on #GP (#6): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                           cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                    }
-                    else if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
-                        Bs3TestFailedF("Bytes touched on #GP: cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                }
-
-                if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
-                    Bs3TestFailedF("Leading bytes touched (#7): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - off - cbIdtr, bFiller))
-                    Bs3TestFailedF("Trailing bytes touched (#7): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-
-                g_usBs3TestStep++;
-            }
-        }
-
-        /* Expand down (weird).  Inverted valid area compared to expand up,
-           so a limit of zero give us a valid range for 0001..0ffffh (instead of
-           a segment with one valid byte at 0000h).  Whereas a limit of 0fffeh
-           means one valid byte at 0ffffh, and a limit of 0ffffh means none
-           (because in a normal expand up the 0ffffh means all 64KB are
-           accessible). */
-        Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
-        for (off = 0; off < 8; off++)
-        {
-            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
-            {
-                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-
-                if (off > cbLimit)
-                {
-                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                    if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
-                        Bs3TestFailedF("Not all bytes touched (#8): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                    if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
-                        Bs3TestFailedF("Mismatch (#8): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
-                    if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
-                        Bs3TestFailedF("286: Top base byte isn't 0xff (#8): %#x\n", abBuf[off + cbIdtr - 1]);
-                }
-                else
-                {
-                    if (pWorker->fSs)
-                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                    else
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
-                        Bs3TestFailedF("Bytes touched on #GP: cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                }
-
-                if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
-                    Bs3TestFailedF("Leading bytes touched (#9): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-                if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - off - cbIdtr, bFiller))
-                    Bs3TestFailedF("Trailing bytes touched (#9): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
-                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
-
-                g_usBs3TestStep++;
-            }
-        }
-
-        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
-        CtxUdExpected.rbx.u = Ctx.rbx.u;
-        CtxUdExpected.ss = Ctx.ss;
-        CtxUdExpected.ds = Ctx.ds;
-    }
-
-    /*
-     * Play with the paging.
-     */
-    if (   BS3_MODE_IS_PAGED(bTestMode)
-        && (!pWorker->fSs || bRing == 3) /* SS.DPL == CPL, we'll get some tiled ring-3 selector here.  */
-        && (pbTest = (uint8_t BS3_FAR *)Bs3MemGuardedTestPageAlloc(BS3MEMKIND_TILED)) != NULL)
-    {
-        RTCCUINTXREG uFlatTest = Bs3SelPtrToFlat(pbTest);
-
-        /*
-         * Slide the buffer towards the trailing guard page.  We'll observe the
-         * first word being written entirely separately from the 2nd dword/qword.
-         */
-        for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-        {
-            Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller, cbIdtr * 2);
-            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off + cbIdtr <= X86_PAGE_SIZE)
-            {
-                CtxUdExpected.rbx = Ctx.rbx;
-                CtxUdExpected.ss  = Ctx.ss;
-                CtxUdExpected.ds  = Ctx.ds;
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                    Bs3TestFailedF("Mismatch (#9): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-            }
-            else
-            {
-                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
-                                          uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                if (   off <= X86_PAGE_SIZE - 2
-                    && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
-                    Bs3TestPrintf("Mismatch (#10): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
-                                  pbExpected, &pbTest[off], off);
-                if (   off < X86_PAGE_SIZE - 2
-                    && !ASMMemIsAllU8(&pbTest[off + 2], X86_PAGE_SIZE - off - 2, bFiller))
-                    Bs3TestPrintf("Wrote partial base on #PF (#10): bFiller=%#x, got %.*Rhxs; off=%#x\n",
-                                  bFiller, X86_PAGE_SIZE - off - 2, &pbTest[off + 2], off);
-                if (off == X86_PAGE_SIZE - 1 && pbTest[off] != bFiller)
-                    Bs3TestPrintf("Wrote partial limit on #PF (#10): Expected %02x, got %02x\n", bFiller, pbTest[off]);
-            }
-            g_usBs3TestStep++;
-        }
-
-        /*
-         * Now, do it the other way around. It should look normal now since writing
-         * the limit will #PF first and nothing should be written.
-         */
-        for (off = cbIdtr + 4; off >= -cbIdtr - 4; off--)
-        {
-            Bs3MemSet(pbTest, bFiller, 48);
-            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off >= 0)
-            {
-                CtxUdExpected.rbx = Ctx.rbx;
-                CtxUdExpected.ss  = Ctx.ss;
-                CtxUdExpected.ds  = Ctx.ds;
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                    Bs3TestFailedF("Mismatch (#11): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-            }
-            else
-            {
-                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0), uFlatTest + off);
-                if (   -off < cbIdtr
-                    && !ASMMemIsAllU8(pbTest, cbIdtr + off, bFiller))
-                    Bs3TestPrintf("Wrote partial content on #PF (#12): bFiller=%#x, found %.*Rhxs; off=%d\n",
-                                  bFiller, cbIdtr + off, pbTest, off);
-            }
-            if (!ASMMemIsAllU8(&pbTest[RT_MAX(cbIdtr + off, 0)], 16, bFiller))
-                Bs3TestPrintf("Wrote beyond expected area (#13): bFiller=%#x, found %.16Rhxs; off=%d\n",
-                              bFiller, &pbTest[RT_MAX(cbIdtr + off, 0)], off);
-            g_usBs3TestStep++;
-        }
-
-        /*
-         * Combine paging and segment limit and check ordering.
-         * This is kind of interesting here since it the instruction seems to
-         * be doing two separate writes.
-         */
-        if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
-            && !BS3_MODE_IS_64BIT_CODE(bTestMode))
-        {
-            uint16_t cbLimit;
-
-            Bs3GdteTestPage00 = Bs3Gdte_DATA16;
-            Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
-            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
-            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
-            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
-
-            if (pWorker->fSs)
-                CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
-            else
-                CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-
-            /* Expand up (normal), approaching tail guard page. */
-            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-            {
-                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
-                {
-                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                    Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller, cbIdtr * 2);
-                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                    if (off + cbIdtr <= cbLimit + 1)
-                    {
-                        /* No #GP, but maybe #PF. */
-                        if (off + cbIdtr <= X86_PAGE_SIZE)
-                        {
-                            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                            if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                                Bs3TestFailedF("Mismatch (#14): expected %.*Rhxs, got %.*Rhxs\n",
-                                               cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-                        }
-                        else
-                        {
-                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
-                                                      uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                            if (   off <= X86_PAGE_SIZE - 2
-                                && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
-                                Bs3TestPrintf("Mismatch (#15): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
-                                              pbExpected, &pbTest[off], off);
-                            cb = X86_PAGE_SIZE - off - 2;
-                            if (   off < X86_PAGE_SIZE - 2
-                                && !ASMMemIsAllU8(&pbTest[off + 2], cb, bFiller))
-                                Bs3TestPrintf("Wrote partial base on #PF (#15): bFiller=%#x, got %.*Rhxs; off=%#x\n",
-                                              bFiller, cb, &pbTest[off + 2], off);
-                            if (off == X86_PAGE_SIZE - 1 && pbTest[off] != bFiller)
-                                Bs3TestPrintf("Wrote partial limit on #PF (#15): Expected %02x, got %02x\n", bFiller, pbTest[off]);
-                        }
-                    }
-                    else if (off + 2 <= cbLimit + 1)
-                    {
-                        /* [ig]tr.limit writing does not cause #GP, but may cause #PG, if not writing the base causes #GP. */
-                        if (off <= X86_PAGE_SIZE - 2)
-                        {
-                            if (pWorker->fSs)
-                                bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                            else
-                                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                            if (Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
-                                Bs3TestPrintf("Mismatch (#16): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
-                                              pbExpected, &pbTest[off], off);
-                            cb = X86_PAGE_SIZE - off - 2;
-                            if (   off < X86_PAGE_SIZE - 2
-                                && !ASMMemIsAllU8(&pbTest[off + 2], cb, bFiller))
-                                Bs3TestPrintf("Wrote partial base with limit (#16): bFiller=%#x, got %.*Rhxs; off=%#x\n",
-                                              bFiller, cb, &pbTest[off + 2], off);
-                        }
-                        else
-                        {
-                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
-                                                      uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                            if (   off < X86_PAGE_SIZE
-                                && !ASMMemIsAllU8(&pbTest[off], X86_PAGE_SIZE - off, bFiller))
-                                Bs3TestPrintf("Mismatch (#16): Partial limit write on #PF: bFiller=%#x, got %.*Rhxs\n",
-                                              bFiller, X86_PAGE_SIZE - off, &pbTest[off]);
-                        }
-                    }
-                    else
-                    {
-                        /* #GP/#SS on limit. */
-                        if (pWorker->fSs)
-                            bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                        else
-                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                        if (   off < X86_PAGE_SIZE
-                            && !ASMMemIsAllU8(&pbTest[off], X86_PAGE_SIZE - off, bFiller))
-                            Bs3TestPrintf("Mismatch (#17): Partial write on #GP: bFiller=%#x, got %.*Rhxs\n",
-                                          bFiller, X86_PAGE_SIZE - off, &pbTest[off]);
-                    }
-
-                    cb = RT_MIN(cbIdtr * 2, off - (X86_PAGE_SIZE - cbIdtr*2));
-                    if (!ASMMemIsAllU8(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], cb, bFiller))
-                        Bs3TestFailedF("Leading bytes touched (#18): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
-                                       cbIdtr, off, cbLimit, bFiller, cb, pbTest[X86_PAGE_SIZE - cbIdtr * 2]);
-
-                    g_usBs3TestStep++;
-
-                    /* Set DS to 0 and check that we get #GP(0). */
-                    if (!pWorker->fSs)
-                    {
-                        Ctx.ds = 0;
-                        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                        Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-                        g_usBs3TestStep++;
-                    }
-                }
-            }
-
-            /* Expand down. */
-            pbTest    -= X86_PAGE_SIZE; /* Note! we're backing up a page to simplify things */
-            uFlatTest -= X86_PAGE_SIZE;
-
-            Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
-            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
-            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
-            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
-
-            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-            {
-                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
-                {
-                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                    Bs3MemSet(&pbTest[X86_PAGE_SIZE], bFiller, cbIdtr * 2);
-                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                    if (cbLimit < off && off >= X86_PAGE_SIZE)
-                    {
-                        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                        if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                            Bs3TestFailedF("Mismatch (#19): expected %.*Rhxs, got %.*Rhxs\n",
-                                           cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-                        cb = X86_PAGE_SIZE + cbIdtr*2 - off;
-                        if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], cb, bFiller))
-                            Bs3TestFailedF("Trailing bytes touched (#20): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
-                                           cbIdtr, off, cbLimit, bFiller, cb, pbTest[off + cbIdtr]);
-                    }
-                    else
-                    {
-                        if (cbLimit < off && off < X86_PAGE_SIZE)
-                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
-                                                      uFlatTest + off);
-                        else if (pWorker->fSs)
-                            bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                        else
-                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                        cb = cbIdtr*2;
-                        if (!ASMMemIsAllU8(&pbTest[X86_PAGE_SIZE], cb, bFiller))
-                            Bs3TestFailedF("Trailing bytes touched (#20): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
-                                           cbIdtr, off, cbLimit, bFiller, cb, pbTest[X86_PAGE_SIZE]);
-                    }
-                    g_usBs3TestStep++;
-                }
-            }
-
-            pbTest    += X86_PAGE_SIZE;
-            uFlatTest += X86_PAGE_SIZE;
-        }
-
-        Bs3MemGuardedTestPageFree(pbTest);
-    }
-
-    /*
-     * Check non-canonical 64-bit space.
-     */
-    if (   BS3_MODE_IS_64BIT_CODE(bTestMode)
-        && (pbTest = (uint8_t BS3_FAR *)Bs3PagingSetupCanonicalTraps()) != NULL)
-    {
-        /* Make our references relative to the gap. */
-        pbTest += g_cbBs3PagingOneCanonicalTrap;
-
-        /* Hit it from below. */
-        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
-        {
-            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0x0000800000000000) + off;
-            Bs3MemSet(&pbTest[-64], bFiller, 64*2);
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off + cbIdtr <= 0)
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                    Bs3TestFailedF("Mismatch (#21): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-            }
-            else
-            {
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                if (off <= -2 && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
-                    Bs3TestFailedF("Mismatch (#21): expected limit %.2Rhxs, got %.2Rhxs\n", pbExpected, &pbTest[off]);
-                off2 = off <= -2 ? 2 : 0;
-                cb   = cbIdtr - off2;
-                if (!ASMMemIsAllU8(&pbTest[off + off2], cb, bFiller))
-                    Bs3TestFailedF("Mismatch (#21): touched base %.*Rhxs, got %.*Rhxs\n",
-                                   cb, &pbExpected[off], cb, &pbTest[off + off2]);
-            }
-            if (!ASMMemIsAllU8(&pbTest[off - 16], 16, bFiller))
-                Bs3TestFailedF("Leading bytes touched (#21): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off]);
-            if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], 16, bFiller))
-                Bs3TestFailedF("Trailing bytes touched (#21): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off + cbIdtr]);
-        }
-
-        /* Hit it from above. */
-        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
-        {
-            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0xffff800000000000) + off;
-            Bs3MemSet(&pbTest[-64], bFiller, 64*2);
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off >= 0)
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
-                    Bs3TestFailedF("Mismatch (#22): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
-            }
-            else
-            {
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                if (!ASMMemIsAllU8(&pbTest[off], cbIdtr, bFiller))
-                    Bs3TestFailedF("Mismatch (#22): touched base %.*Rhxs, got %.*Rhxs\n",
-                                   cbIdtr, &pbExpected[off], cbIdtr, &pbTest[off]);
-            }
-            if (!ASMMemIsAllU8(&pbTest[off - 16], 16, bFiller))
-                Bs3TestFailedF("Leading bytes touched (#22): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off]);
-            if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], 16, bFiller))
-                Bs3TestFailedF("Trailing bytes touched (#22): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off + cbIdtr]);
-        }
-
-    }
-}
-
-
-# define bs3CpuBasic2_sidt_sgdt_Common BS3_CMN_NM(bs3CpuBasic2_sidt_sgdt_Common)
-BS3_DECL_NEAR(void) bs3CpuBasic2_sidt_sgdt_Common(uint8_t bTestMode, BS3CB2SIDTSGDT const BS3_FAR *paWorkers, unsigned cWorkers,
-                                                  uint8_t const *pbExpected)
-{
-    unsigned idx;
-    unsigned bRing;
-    unsigned iStep = 0;
-
-    /* Note! We skip the SS checks for ring-0 since we badly mess up SS in the
-             test and don't want to bother with double faults. */
-    for (bRing = 0; bRing <= 3; bRing++)
-    {
-        for (idx = 0; idx < cWorkers; idx++)
-            if (    (paWorkers[idx].bMode & (bTestMode & BS3_MODE_CODE_MASK))
-                && (!paWorkers[idx].fSs || bRing != 0 /** @todo || BS3_MODE_IS_64BIT_SYS(bTestMode)*/ ))
-            {
-                g_usBs3TestStep = iStep;
-                bs3CpuBasic2_sidt_sgdt_One(&paWorkers[idx], bTestMode, bRing, pbExpected);
-                iStep += 1000;
-            }
-        if (BS3_MODE_IS_RM_OR_V86(bTestMode))
-            break;
-    }
-}
-
-BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_sidt)(uint8_t bMode)
-{
-    union
-    {
-        RTIDTR  Idtr;
-        uint8_t ab[16];
-    } Expected;
-
-    g_pszTestMode = Bs3GetModeName(bMode);
-    g_bTestMode   = bMode;
-    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
-
-
-    /*
-     * Pass to common worker which is only compiled once per mode.
-     */
-    Bs3MemZero(&Expected, sizeof(Expected));
-    ASMGetIDTR(&Expected.Idtr);
-    bs3CpuBasic2_sidt_sgdt_Common(bMode, g_aSidtWorkers, RT_ELEMENTS(g_aSidtWorkers), Expected.ab);
-
-    /*
-     * Re-initialize the IDT.
-     */
-    Bs3TrapReInit();
-    return 0;
-}
-
-
-BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_sgdt)(uint8_t bMode)
-{
-    uint64_t const uOrgAddr = Bs3Lgdt_Gdt.uAddr;
-    uint64_t       uNew     = 0;
-    union
-    {
-        RTGDTR  Gdtr;
-        uint8_t ab[16];
-    } Expected;
-
-    g_pszTestMode = Bs3GetModeName(bMode);
-    g_bTestMode   = bMode;
-    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
-
-    /*
-     * If paged mode, try push the GDT way up.
-     */
-    if (BS3_MODE_IS_PAGED(bMode))
-    {
-/** @todo loading non-canonical base addresses.   */
-        int rc;
-        uNew  = BS3_MODE_IS_64BIT_SYS(bMode) ? UINT64_C(0xffff80fedcb70000) : UINT64_C(0xc2d28000);
-        uNew |= uOrgAddr & X86_PAGE_OFFSET_MASK;
-        rc = Bs3PagingAlias(uNew, uOrgAddr, Bs3Lgdt_Gdt.cb, X86_PTE_P | X86_PTE_RW | X86_PTE_US | X86_PTE_D | X86_PTE_A);
-        if (RT_SUCCESS(rc))
-        {
-            Bs3Lgdt_Gdt.uAddr = uNew;
-            Bs3UtilSetFullGdtr(Bs3Lgdt_Gdt.cb, uNew);
-        }
-    }
-
-    /*
-     * Pass to common worker which is only compiled once per mode.
-     */
-    Bs3MemZero(&Expected, sizeof(Expected));
-    ASMGetGDTR(&Expected.Gdtr);
-    bs3CpuBasic2_sidt_sgdt_Common(bMode, g_aSgdtWorkers, RT_ELEMENTS(g_aSgdtWorkers), Expected.ab);
-
-    /*
-     * Unalias the GDT.
-     */
-    if (uNew != 0)
-    {
-        Bs3Lgdt_Gdt.uAddr = uOrgAddr;
-        Bs3UtilSetFullGdtr(Bs3Lgdt_Gdt.cb, uOrgAddr);
-        Bs3PagingUnalias(uNew, Bs3Lgdt_Gdt.cb);
-    }
-
-    /*
-     * Re-initialize the IDT.
-     */
-    Bs3TrapReInit();
-    return 0;
-}
-
-
-
-/*
- * LIDT & LGDT
- */
-
-/**
- * Executes one round of LIDT and LGDT tests using one assembly worker.
- *
- * This is written with driving everything from the 16-bit or 32-bit worker in
- * mind, i.e. not assuming the test bitcount is the same as the current.
- */
-# define bs3CpuBasic2_lidt_lgdt_One BS3_CMN_NM(bs3CpuBasic2_lidt_lgdt_One)
-BS3_DECL_NEAR(void) bs3CpuBasic2_lidt_lgdt_One(BS3CB2SIDTSGDT const BS3_FAR *pWorker, uint8_t bTestMode, uint8_t bRing,
-                                               uint8_t const *pbRestore, size_t cbRestore, uint8_t const *pbExpected)
-{
-    static const struct
-    {
-        bool        fGP;
-        uint16_t    cbLimit;
-        uint64_t    u64Base;
-    } s_aValues64[] =
-    {
-        { false, 0x0000, UINT64_C(0x0000000000000000) },
-        { false, 0x0001, UINT64_C(0x0000000000000001) },
-        { false, 0x0002, UINT64_C(0x0000000000000010) },
-        { false, 0x0003, UINT64_C(0x0000000000000123) },
-        { false, 0x0004, UINT64_C(0x0000000000001234) },
-        { false, 0x0005, UINT64_C(0x0000000000012345) },
-        { false, 0x0006, UINT64_C(0x0000000000123456) },
-        { false, 0x0007, UINT64_C(0x0000000001234567) },
-        { false, 0x0008, UINT64_C(0x0000000012345678) },
-        { false, 0x0009, UINT64_C(0x0000000123456789) },
-        { false, 0x000a, UINT64_C(0x000000123456789a) },
-        { false, 0x000b, UINT64_C(0x00000123456789ab) },
-        { false, 0x000c, UINT64_C(0x0000123456789abc) },
-        { false, 0x001c, UINT64_C(0x00007ffffeefefef) },
-        { false, 0xffff, UINT64_C(0x00007fffffffffff) },
-        {  true, 0xf3f1, UINT64_C(0x0000800000000000) },
-        {  true, 0x0000, UINT64_C(0x0000800000000000) },
-        {  true, 0x0000, UINT64_C(0x0000800000000333) },
-        {  true, 0x00f0, UINT64_C(0x0001000000000000) },
-        {  true, 0x0ff0, UINT64_C(0x0012000000000000) },
-        {  true, 0x0eff, UINT64_C(0x0123000000000000) },
-        {  true, 0xe0fe, UINT64_C(0x1234000000000000) },
-        {  true, 0x00ad, UINT64_C(0xffff300000000000) },
-        {  true, 0x0000, UINT64_C(0xffff7fffffffffff) },
-        {  true, 0x00f0, UINT64_C(0xffff7fffffffffff) },
-        { false, 0x5678, UINT64_C(0xffff800000000000) },
-        { false, 0x2969, UINT64_C(0xffffffffffeefefe) },
-        { false, 0x1221, UINT64_C(0xffffffffffffffff) },
-        { false, 0x1221, UINT64_C(0xffffffffffffffff) },
-    };
-    static const struct
-    {
-        uint16_t    cbLimit;
-        uint32_t    u32Base;
-    } s_aValues32[] =
-    {
-        { 0xdfdf, UINT32_C(0xefefefef) },
-        { 0x0000, UINT32_C(0x00000000) },
-        { 0x0001, UINT32_C(0x00000001) },
-        { 0x0002, UINT32_C(0x00000012) },
-        { 0x0003, UINT32_C(0x00000123) },
-        { 0x0004, UINT32_C(0x00001234) },
-        { 0x0005, UINT32_C(0x00012345) },
-        { 0x0006, UINT32_C(0x00123456) },
-        { 0x0007, UINT32_C(0x01234567) },
-        { 0x0008, UINT32_C(0x12345678) },
-        { 0x0009, UINT32_C(0x80204060) },
-        { 0x000a, UINT32_C(0xddeeffaa) },
-        { 0x000b, UINT32_C(0xfdecdbca) },
-        { 0x000c, UINT32_C(0x6098456b) },
-        { 0x000d, UINT32_C(0x98506099) },
-        { 0x000e, UINT32_C(0x206950bc) },
-        { 0x000f, UINT32_C(0x9740395d) },
-        { 0x0334, UINT32_C(0x64a9455e) },
-        { 0xb423, UINT32_C(0xd20b6eff) },
-        { 0x4955, UINT32_C(0x85296d46) },
-        { 0xffff, UINT32_C(0x07000039) },
-        { 0xefe1, UINT32_C(0x0007fe00) },
-    };
-
-    BS3TRAPFRAME        TrapCtx;
-    BS3REGCTX           Ctx;
-    BS3REGCTX           CtxUdExpected;
-    BS3REGCTX           TmpCtx;
-    uint8_t             abBufLoad[40];          /* Test buffer w/ misalignment test space and some (cbIdtr) extra guard. */
-    uint8_t             abBufSave[32];          /* For saving the result after loading. */
-    uint8_t             abBufRestore[24];       /* For restoring sane value (same seg as abBufSave!). */
-    uint8_t             abExpectedFilled[32];   /* Same as pbExpected, except it's filled with bFiller2 instead of zeros. */
-    uint8_t BS3_FAR    *pbBufSave;              /* Correctly aligned pointer into abBufSave. */
-    uint8_t BS3_FAR    *pbBufRestore;           /* Correctly aligned pointer into abBufRestore. */
-    uint8_t const       cbIdtr        = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 2+8 : 2+4;
-    uint8_t const       cbBaseLoaded  = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 8
-                                      : BS3_MODE_IS_16BIT_CODE(bTestMode) == !(pWorker->fFlags & BS3CB2SIDTSGDT_F_OPSIZE)
-                                      ? 3 : 4;
-    bool const          f286          = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80286;
-    uint8_t const       bTop16BitBase = f286 ? 0xff : 0x00;
-    uint8_t             bFiller1;               /* For filling abBufLoad.  */
-    uint8_t             bFiller2;               /* For filling abBufSave and expectations. */
-    int                 off;
-    uint8_t BS3_FAR    *pbTest;
-    unsigned            i;
-
-    /* make sure they're allocated  */
-    Bs3MemZero(&Ctx, sizeof(Ctx));
-    Bs3MemZero(&CtxUdExpected, sizeof(CtxUdExpected));
-    Bs3MemZero(&TmpCtx, sizeof(TmpCtx));
-    Bs3MemZero(&TrapCtx, sizeof(TrapCtx));
-    Bs3MemZero(abBufSave, sizeof(abBufSave));
-    Bs3MemZero(abBufLoad, sizeof(abBufLoad));
-    Bs3MemZero(abBufRestore, sizeof(abBufRestore));
-
-    /*
-     * Create a context, giving this routine some more stack space.
-     *  - Point the context at our LIDT [xBX] + SIDT [xDI] + LIDT [xSI] + UD2 combo.
-     *  - Point DS/SS:xBX at abBufLoad.
-     *  - Point ES:xDI at abBufSave.
-     *  - Point ES:xSI at abBufRestore.
-     */
-    Bs3RegCtxSaveEx(&Ctx, bTestMode, 256 /*cbExtraStack*/);
-    Bs3RegCtxSetRipCsFromLnkPtr(&Ctx, pWorker->fpfnWorker);
-    if (BS3_MODE_IS_16BIT_SYS(bTestMode))
-        g_uBs3TrapEipHint = Ctx.rip.u32;
-    Ctx.rflags.u16 &= ~X86_EFL_IF;
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
-
-    pbBufSave = abBufSave;
-    if ((BS3_FP_OFF(pbBufSave) + 2) & 7)
-        pbBufSave += 8 - ((BS3_FP_OFF(pbBufSave) + 2) & 7);
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rdi, &Ctx.es, pbBufSave);
-
-    pbBufRestore = abBufRestore;
-    if ((BS3_FP_OFF(pbBufRestore) + 2) & 7)
-        pbBufRestore += 8 - ((BS3_FP_OFF(pbBufRestore) + 2) & 7);
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rsi, &Ctx.es, pbBufRestore);
-    Bs3MemCpy(pbBufRestore, pbRestore, cbRestore);
-
-    if (!BS3_MODE_IS_RM_OR_V86(bTestMode))
-        Bs3RegCtxConvertToRingX(&Ctx, bRing);
-
-    /* For successful SIDT attempts, we'll stop at the UD2. */
-    Bs3MemCpy(&CtxUdExpected, &Ctx, sizeof(Ctx));
-    CtxUdExpected.rip.u += pWorker->cbInstr;
-
-    /*
-     * Check that it works at all.
-     */
-    Bs3MemZero(abBufLoad, sizeof(abBufLoad));
-    Bs3MemCpy(abBufLoad, pbBufRestore, cbIdtr);
-    Bs3MemZero(abBufSave, sizeof(abBufSave));
-    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-    if (bRing != 0)
-        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-    else
-    {
-        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-        if (Bs3MemCmp(pbBufSave, pbExpected, cbIdtr * 2) != 0)
-            Bs3TestFailedF("Mismatch (%s, #1): expected %.*Rhxs, got %.*Rhxs\n",
-                           pWorker->pszDesc, cbIdtr*2, pbExpected, cbIdtr*2, pbBufSave);
-    }
-    g_usBs3TestStep++;
-
-    /* Determine two filler bytes that doesn't appear in the previous result or our expectations. */
-    bFiller1 = ~0x55;
-    while (   Bs3MemChr(pbBufSave, bFiller1, cbIdtr) != NULL
-           || Bs3MemChr(pbRestore, bFiller1, cbRestore) != NULL
-           || bFiller1 == 0xff)
-        bFiller1++;
-    bFiller2 = 0x33;
-    while (   Bs3MemChr(pbBufSave, bFiller2, cbIdtr) != NULL
-           || Bs3MemChr(pbRestore, bFiller2, cbRestore) != NULL
-           || bFiller2 == 0xff
-           || bFiller2 == bFiller1)
-        bFiller2++;
-    Bs3MemSet(abExpectedFilled, bFiller2, sizeof(abExpectedFilled));
-    Bs3MemCpy(abExpectedFilled, pbExpected, cbIdtr);
-
-    /* Again with a buffer filled with a byte not occuring in the previous result. */
-    Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-    Bs3MemCpy(abBufLoad, pbBufRestore, cbIdtr);
-    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-    if (bRing != 0)
-        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-    else
-    {
-        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-        if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-            Bs3TestFailedF("Mismatch (%s, #2): expected %.*Rhxs, got %.*Rhxs\n",
-                           pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-    }
-    g_usBs3TestStep++;
-
-    /*
-     * Try loading a bunch of different limit+base value to check what happens,
-     * especially what happens wrt the top part of the base in 16-bit mode.
-     */
-    if (BS3_MODE_IS_64BIT_CODE(bTestMode))
-    {
-        for (i = 0; i < RT_ELEMENTS(s_aValues64); i++)
-        {
-            Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-            Bs3MemCpy(&abBufLoad[0], &s_aValues64[i].cbLimit, 2);
-            Bs3MemCpy(&abBufLoad[2], &s_aValues64[i].u64Base, 8);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (bRing != 0 || s_aValues64[i].fGP)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (   Bs3MemCmp(&pbBufSave[0], &s_aValues64[i].cbLimit, 2) != 0
-                    || Bs3MemCmp(&pbBufSave[2], &s_aValues64[i].u64Base, 8) != 0
-                    || !ASMMemIsAllU8(&pbBufSave[10], cbIdtr, bFiller2))
-                    Bs3TestFailedF("Mismatch (%s, #2): expected %04RX16:%016RX64, fillers %#x %#x, got %.*Rhxs\n",
-                                   pWorker->pszDesc, s_aValues64[i].cbLimit, s_aValues64[i].u64Base,
-                                   bFiller1, bFiller2, cbIdtr*2, pbBufSave);
-            }
-            g_usBs3TestStep++;
-        }
-    }
-    else
-    {
-        for (i = 0; i < RT_ELEMENTS(s_aValues32); i++)
-        {
-            Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-            Bs3MemCpy(&abBufLoad[0], &s_aValues32[i].cbLimit, 2);
-            Bs3MemCpy(&abBufLoad[2], &s_aValues32[i].u32Base, cbBaseLoaded);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (bRing != 0)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (   Bs3MemCmp(&pbBufSave[0], &s_aValues32[i].cbLimit, 2) != 0
-                    || Bs3MemCmp(&pbBufSave[2], &s_aValues32[i].u32Base, cbBaseLoaded) != 0
-                    || (   cbBaseLoaded != 4
-                        && pbBufSave[2+3] != bTop16BitBase)
-                    || !ASMMemIsAllU8(&pbBufSave[8], cbIdtr, bFiller2))
-                    Bs3TestFailedF("Mismatch (%s,#3): loaded %04RX16:%08RX32, fillers %#x %#x%s, got %.*Rhxs\n",
-                                   pWorker->pszDesc, s_aValues32[i].cbLimit, s_aValues32[i].u32Base, bFiller1, bFiller2,
-                                   f286 ? ", 286" : "", cbIdtr*2, pbBufSave);
-            }
-            g_usBs3TestStep++;
-        }
-    }
-
-    /*
-     * Slide the buffer along 8 bytes to cover misalignment.
-     */
-    for (off = 0; off < 8; off++)
-    {
-        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &abBufLoad[off]);
-        CtxUdExpected.rbx.u = Ctx.rbx.u;
-
-        Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-        Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
-        Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-        if (bRing != 0)
-            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-        else
-        {
-            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-            if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                Bs3TestFailedF("Mismatch (%s, #4): expected %.*Rhxs, got %.*Rhxs\n",
-                               pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-        }
-        g_usBs3TestStep++;
-    }
-    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
-    CtxUdExpected.rbx.u = Ctx.rbx.u;
-
-    /*
-     * Play with the selector limit if the target mode supports limit checking
-     * We use BS3_SEL_TEST_PAGE_00 for this
-     */
-    if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
-        && !BS3_MODE_IS_64BIT_CODE(bTestMode))
-    {
-        uint16_t cbLimit;
-        uint32_t uFlatBuf = Bs3SelPtrToFlat(abBufLoad);
-        Bs3GdteTestPage00 = Bs3Gdte_DATA16;
-        Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
-        Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatBuf;
-        Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatBuf >> 16);
-        Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatBuf >> 24);
-
-        if (pWorker->fSs)
-            CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
-        else
-            CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-
-        /* Expand up (normal). */
-        for (off = 0; off < 8; off++)
-        {
-            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
-            {
-                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-
-                Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-                Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
-                Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (bRing != 0)
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                else if (off + cbIdtr <= cbLimit + 1)
-                {
-                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                    if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                        Bs3TestFailedF("Mismatch (%s, #5): expected %.*Rhxs, got %.*Rhxs\n",
-                                       pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-                }
-                else if (pWorker->fSs)
-                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                else
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                g_usBs3TestStep++;
-
-                /* Again with zero limit and messed up base (should trigger tripple fault if partially loaded). */
-                abBufLoad[off] = abBufLoad[off + 1] = 0;
-                abBufLoad[off + 2] |= 1;
-                abBufLoad[off + cbIdtr - 2] ^= 0x5a;
-                abBufLoad[off + cbIdtr - 1] ^= 0xa5;
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (bRing != 0)
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                else if (off + cbIdtr <= cbLimit + 1)
-                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                else if (pWorker->fSs)
-                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                else
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            }
-        }
-
-        /* Expand down (weird).  Inverted valid area compared to expand up,
-           so a limit of zero give us a valid range for 0001..0ffffh (instead of
-           a segment with one valid byte at 0000h).  Whereas a limit of 0fffeh
-           means one valid byte at 0ffffh, and a limit of 0ffffh means none
-           (because in a normal expand up the 0ffffh means all 64KB are
-           accessible). */
-        Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
-        for (off = 0; off < 8; off++)
-        {
-            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
-            {
-                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-
-                Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
-                Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
-                Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (bRing != 0)
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                else if (off > cbLimit)
-                {
-                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                    if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                        Bs3TestFailedF("Mismatch (%s, #6): expected %.*Rhxs, got %.*Rhxs\n",
-                                       pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-                }
-                else if (pWorker->fSs)
-                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                else
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-               g_usBs3TestStep++;
-
-               /* Again with zero limit and messed up base (should trigger triple fault if partially loaded). */
-               abBufLoad[off] = abBufLoad[off + 1] = 0;
-               abBufLoad[off + 2] |= 3;
-               abBufLoad[off + cbIdtr - 2] ^= 0x55;
-               abBufLoad[off + cbIdtr - 1] ^= 0xaa;
-               Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-               if (bRing != 0)
-                   bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-               else if (off > cbLimit)
-                   bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-               else if (pWorker->fSs)
-                   bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-               else
-                   bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            }
-        }
-
-        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
-        CtxUdExpected.rbx.u = Ctx.rbx.u;
-        CtxUdExpected.ss = Ctx.ss;
-        CtxUdExpected.ds = Ctx.ds;
-    }
-
-    /*
-     * Play with the paging.
-     */
-    if (   BS3_MODE_IS_PAGED(bTestMode)
-        && (!pWorker->fSs || bRing == 3) /* SS.DPL == CPL, we'll get some tiled ring-3 selector here.  */
-        && (pbTest = (uint8_t BS3_FAR *)Bs3MemGuardedTestPageAlloc(BS3MEMKIND_TILED)) != NULL)
-    {
-        RTCCUINTXREG uFlatTest = Bs3SelPtrToFlat(pbTest);
-
-        /*
-         * Slide the load buffer towards the trailing guard page.
-         */
-        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[X86_PAGE_SIZE]);
-        CtxUdExpected.ss = Ctx.ss;
-        CtxUdExpected.ds = Ctx.ds;
-        for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-        {
-            Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller1, cbIdtr*2);
-            if (off < X86_PAGE_SIZE)
-                Bs3MemCpy(&pbTest[off], pbBufRestore, RT_MIN(X86_PAGE_SIZE - off, cbIdtr));
-            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (bRing != 0)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else if (off + cbIdtr <= X86_PAGE_SIZE)
-            {
-                CtxUdExpected.rbx = Ctx.rbx;
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr*2) != 0)
-                    Bs3TestFailedF("Mismatch (%s, #7): expected %.*Rhxs, got %.*Rhxs\n",
-                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-            }
-            else
-                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-            g_usBs3TestStep++;
-
-            /* Again with zero limit and maybe messed up base as well (triple fault if buggy).
-               The 386DX-40 here triple faults (or something) with off == 0xffe, nothing else. */
-            if (   off < X86_PAGE_SIZE && off + cbIdtr > X86_PAGE_SIZE
-                && (   off != X86_PAGE_SIZE - 2
-                    || (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) != BS3CPU_80386)
-                )
-            {
-                pbTest[off] = 0;
-                if (off + 1 < X86_PAGE_SIZE)
-                    pbTest[off + 1] = 0;
-                if (off + 2 < X86_PAGE_SIZE)
-                    pbTest[off + 2] |= 7;
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (bRing != 0)
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                else
-                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                g_usBs3TestStep++;
-            }
-        }
-
-        /*
-         * Now, do it the other way around. It should look normal now since writing
-         * the limit will #PF first and nothing should be written.
-         */
-        for (off = cbIdtr + 4; off >= -cbIdtr - 4; off--)
-        {
-            Bs3MemSet(pbTest, bFiller1, 48);
-            if (off >= 0)
-                Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
-            else if (off + cbIdtr > 0)
-                Bs3MemCpy(pbTest, &pbBufRestore[-off], cbIdtr + off);
-            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (bRing != 0)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else if (off >= 0)
-            {
-                CtxUdExpected.rbx = Ctx.rbx;
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr*2) != 0)
-                    Bs3TestFailedF("Mismatch (%s, #8): expected %.*Rhxs, got %.*Rhxs\n",
-                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-            }
-            else
-                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
-            g_usBs3TestStep++;
-
-            /* Again with messed up base as well (triple fault if buggy). */
-            if (off < 0 && off > -cbIdtr)
-            {
-                if (off + 2 >= 0)
-                    pbTest[off + 2] |= 15;
-                pbTest[off + cbIdtr - 1] ^= 0xaa;
-                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                if (bRing != 0)
-                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                else
-                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
-                g_usBs3TestStep++;
-            }
-        }
-
-        /*
-         * Combine paging and segment limit and check ordering.
-         * This is kind of interesting here since it the instruction seems to
-         * actually be doing two separate read, just like it's S[IG]DT counterpart.
-         *
-         * Note! My 486DX4 does a DWORD limit read when the operand size is 32-bit,
-         *       that's what f486Weirdness deals with.
-         */
-        if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
-            && !BS3_MODE_IS_64BIT_CODE(bTestMode))
-        {
-            bool const f486Weirdness = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80486
-                                    && BS3_MODE_IS_32BIT_CODE(bTestMode) == !(pWorker->fFlags & BS3CB2SIDTSGDT_F_OPSIZE);
-            uint16_t   cbLimit;
-
-            Bs3GdteTestPage00 = Bs3Gdte_DATA16;
-            Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
-            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
-            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
-            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
-
-            if (pWorker->fSs)
-                CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
-            else
-                CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-
-            /* Expand up (normal), approaching tail guard page. */
-            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-            {
-                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
-                {
-                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                    Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller1, cbIdtr * 2);
-                    if (off < X86_PAGE_SIZE)
-                        Bs3MemCpy(&pbTest[off], pbBufRestore, RT_MIN(cbIdtr, X86_PAGE_SIZE - off));
-                    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                    if (bRing != 0)
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                    else if (off + cbIdtr <= cbLimit + 1)
-                    {
-                        /* No #GP, but maybe #PF. */
-                        if (off + cbIdtr <= X86_PAGE_SIZE)
-                        {
-                            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                            if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                                Bs3TestFailedF("Mismatch (%s, #9): expected %.*Rhxs, got %.*Rhxs\n",
-                                               pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-                        }
-                        else
-                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                    }
-                    /* No #GP/#SS on limit, but instead #PF? */
-                    else if (  !f486Weirdness
-                             ? off     < cbLimit && off >= 0xfff
-                             : off + 2 < cbLimit && off >= 0xffd)
-                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
-                    /* #GP/#SS on limit or base. */
-                    else if (pWorker->fSs)
-                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                    else
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-
-                    g_usBs3TestStep++;
-
-                    /* Set DS to 0 and check that we get #GP(0). */
-                    if (!pWorker->fSs)
-                    {
-                        Ctx.ds = 0;
-                        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                        Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
-                        g_usBs3TestStep++;
-                    }
-                }
-            }
-
-            /* Expand down. */
-            pbTest    -= X86_PAGE_SIZE; /* Note! we're backing up a page to simplify things */
-            uFlatTest -= X86_PAGE_SIZE;
-
-            Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
-            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
-            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
-            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
-
-            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
-            {
-                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
-                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
-                {
-                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
-                    Bs3MemSet(&pbTest[X86_PAGE_SIZE], bFiller1, cbIdtr * 2);
-                    if (off >= X86_PAGE_SIZE)
-                        Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
-                    else if (off > X86_PAGE_SIZE - cbIdtr)
-                        Bs3MemCpy(&pbTest[X86_PAGE_SIZE], &pbBufRestore[X86_PAGE_SIZE - off], cbIdtr - (X86_PAGE_SIZE - off));
-                    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-                    if (bRing != 0)
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                    else if (cbLimit < off && off >= X86_PAGE_SIZE)
-                    {
-                        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                        if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                            Bs3TestFailedF("Mismatch (%s, #10): expected %.*Rhxs, got %.*Rhxs\n",
-                                           pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-                    }
-                    else if (cbLimit < off && off < X86_PAGE_SIZE)
-                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
-                    else if (pWorker->fSs)
-                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
-                    else
-                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-                    g_usBs3TestStep++;
-                }
-            }
-
-            pbTest    += X86_PAGE_SIZE;
-            uFlatTest += X86_PAGE_SIZE;
-        }
-
-        Bs3MemGuardedTestPageFree(pbTest);
-    }
-
-    /*
-     * Check non-canonical 64-bit space.
-     */
-    if (   BS3_MODE_IS_64BIT_CODE(bTestMode)
-        && (pbTest = (uint8_t BS3_FAR *)Bs3PagingSetupCanonicalTraps()) != NULL)
-    {
-        /* Make our references relative to the gap. */
-        pbTest += g_cbBs3PagingOneCanonicalTrap;
-
-        /* Hit it from below. */
-        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
-        {
-            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0x0000800000000000) + off;
-            Bs3MemSet(&pbTest[-64], bFiller1, 64*2);
-            Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off + cbIdtr > 0 || bRing != 0)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                    Bs3TestFailedF("Mismatch (%s, #11): expected %.*Rhxs, got %.*Rhxs\n",
-                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-            }
-        }
-
-        /* Hit it from above. */
-        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
-        {
-            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0xffff800000000000) + off;
-            Bs3MemSet(&pbTest[-64], bFiller1, 64*2);
-            Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
-            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
-            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
-            if (off < 0 || bRing != 0)
-                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
-            else
-            {
-                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
-                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
-                    Bs3TestFailedF("Mismatch (%s, #19): expected %.*Rhxs, got %.*Rhxs\n",
-                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
-            }
-        }
-
-    }
-}
-
-
-# define bs3CpuBasic2_lidt_lgdt_Common BS3_CMN_NM(bs3CpuBasic2_lidt_lgdt_Common)
-BS3_DECL_NEAR(void) bs3CpuBasic2_lidt_lgdt_Common(uint8_t bTestMode, BS3CB2SIDTSGDT const BS3_FAR *paWorkers, unsigned cWorkers,
-                                                  void const *pvRestore, size_t cbRestore, uint8_t const *pbExpected)
-{
-    unsigned idx;
-    unsigned bRing;
-    unsigned iStep = 0;
-
-    /* Note! We skip the SS checks for ring-0 since we badly mess up SS in the
-             test and don't want to bother with double faults. */
-    for (bRing = BS3_MODE_IS_V86(bTestMode) ? 3 : 0; bRing <= 3; bRing++)
-    {
-        for (idx = 0; idx < cWorkers; idx++)
-            if (    (paWorkers[idx].bMode & (bTestMode & BS3_MODE_CODE_MASK))
-                && (!paWorkers[idx].fSs || bRing != 0 /** @todo || BS3_MODE_IS_64BIT_SYS(bTestMode)*/ )
-                && (   !(paWorkers[idx].fFlags & BS3CB2SIDTSGDT_F_386PLUS)
-                    || (   bTestMode > BS3_MODE_PE16
-                        || (   bTestMode == BS3_MODE_PE16
-                            && (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80386)) ) )
-            {
-                //Bs3TestPrintf("idx=%-2d fpfnWorker=%p fSs=%d cbInstr=%d\n",
-                //              idx, paWorkers[idx].fpfnWorker, paWorkers[idx].fSs, paWorkers[idx].cbInstr);
-                g_usBs3TestStep = iStep;
-                bs3CpuBasic2_lidt_lgdt_One(&paWorkers[idx], bTestMode, bRing, pvRestore, cbRestore, pbExpected);
-                iStep += 1000;
-            }
-        if (BS3_MODE_IS_RM_SYS(bTestMode))
-            break;
-    }
-}
-
-
-BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_lidt)(uint8_t bMode)
-{
-    union
-    {
-        RTIDTR  Idtr;
-        uint8_t ab[32]; /* At least cbIdtr*2! */
-    } Expected;
-
-    g_pszTestMode = Bs3GetModeName(bMode);
-    g_bTestMode   = bMode;
-    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
-
-    /*
-     * Pass to common worker which is only compiled once per mode.
-     */
-    Bs3MemZero(&Expected, sizeof(Expected));
-    ASMGetIDTR(&Expected.Idtr);
-
-    if (BS3_MODE_IS_RM_SYS(bMode))
-        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
-                                      &Bs3Lidt_Ivt, sizeof(Bs3Lidt_Ivt), Expected.ab);
-    else if (BS3_MODE_IS_16BIT_SYS(bMode))
-        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
-                                      &Bs3Lidt_Idt16, sizeof(Bs3Lidt_Idt16), Expected.ab);
-    else if (BS3_MODE_IS_32BIT_SYS(bMode))
-        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
-                                      &Bs3Lidt_Idt32, sizeof(Bs3Lidt_Idt32), Expected.ab);
-    else
-        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
-                                      &Bs3Lidt_Idt64, sizeof(Bs3Lidt_Idt64), Expected.ab);
-
-    /*
-     * Re-initialize the IDT.
-     */
-    Bs3TrapReInit();
-    return 0;
-}
-
-
-BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_lgdt)(uint8_t bMode)
-{
-    union
-    {
-        RTGDTR  Gdtr;
-        uint8_t ab[32]; /* At least cbIdtr*2! */
-    } Expected;
-
-    g_pszTestMode = Bs3GetModeName(bMode);
-    g_bTestMode   = bMode;
-    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
-
-    /*
-     * Pass to common worker which is only compiled once per mode.
-     */
-    if (BS3_MODE_IS_RM_SYS(bMode))
-        ASMSetGDTR((PRTGDTR)&Bs3LgdtDef_Gdt);
-    Bs3MemZero(&Expected, sizeof(Expected));
-    ASMGetGDTR(&Expected.Gdtr);
-
-    bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLgdtWorkers, RT_ELEMENTS(g_aLgdtWorkers),
-                                  &Bs3LgdtDef_Gdt, sizeof(Bs3LgdtDef_Gdt), Expected.ab);
-
-    /*
-     * Re-initialize the IDT.
-     */
-    Bs3TrapReInit();
-    return 0;
-}
-#endif /* TMPL_BITS == 16 */
-
-
 # if ARCH_BITS != 64
 
@@ -3152,31 +1548,4 @@
 }
 
-
-# if 0
-BS3_DECL_FAR(uint8_t) TMPL_NM(bs3CpuBasic2_sidt)(uint8_t bMode)
-{
-    BS3_ASSERT(bMode == TMPL_MODE);
-    return BS3_CMN_FAR_NM(bs3CpuBasic2_sidt)(bMode);
-}
-
-BS3_DECL_FAR(uint8_t) TMPL_NM(bs3CpuBasic2_sgdt)(uint8_t bMode)
-{
-    BS3_ASSERT(bMode == TMPL_MODE);
-    return BS3_CMN_FAR_NM(bs3CpuBasic2_sgdt)(bMode);
-}
-
-BS3_DECL_FAR(uint8_t) TMPL_NM(bs3CpuBasic2_lidt)(uint8_t bMode)
-{
-    BS3_ASSERT(bMode == TMPL_MODE);
-    return BS3_CMN_FAR_NM(bs3CpuBasic2_lidt)(bMode);
-}
-
-BS3_DECL_FAR(uint8_t) TMPL_NM(bs3CpuBasic2_lgdt)(uint8_t bMode)
-{
-    BS3_ASSERT(bMode == TMPL_MODE);
-    return BS3_CMN_FAR_NM(bs3CpuBasic2_lgdt)(bMode);
-}
-# endif
-
 #endif /* BS3_INSTANTIATING_MODE */
 
Index: /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-x0.c
===================================================================
--- /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-x0.c	(revision 60750)
+++ /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2-x0.c	(revision 60750)
@@ -0,0 +1,2870 @@
+/* $Id$ */
+/** @file
+ * BS3Kit - bs3-cpu-basic-2, C test driver code (16-bit).
+ */
+
+/*
+ * Copyright (C) 2007-2016 Oracle Corporation
+ *
+ * This file is part of VirtualBox Open Source Edition (OSE), as
+ * available from http://www.virtualbox.org. This file is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU
+ * General Public License (GPL) as published by the Free Software
+ * Foundation, in version 2 as it comes in the "COPYING" file of the
+ * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+ * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+ *
+ * The contents of this file may alternatively be used under the terms
+ * of the Common Development and Distribution License Version 1.0
+ * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+ * VirtualBox OSE distribution, in which case the provisions of the
+ * CDDL are applicable instead of those of the GPL.
+ *
+ * You may elect to license modified versions of this file under the
+ * terms and conditions of either the GPL or the CDDL or both.
+ */
+
+
+/*********************************************************************************************************************************
+*   Header Files                                                                                                                 *
+*********************************************************************************************************************************/
+#define BS3_USE_X0_TEXT_SEG
+#include <bs3kit.h>
+#include <iprt/asm.h>
+#include <iprt/asm-amd64-x86.h>
+
+
+/*********************************************************************************************************************************
+*   Defined Constants And Macros                                                                                                 *
+*********************************************************************************************************************************/
+#undef  CHECK_MEMBER
+#define CHECK_MEMBER(a_szName, a_szFmt, a_Actual, a_Expected) \
+    do \
+    { \
+        if ((a_Actual) == (a_Expected)) { /* likely */ } \
+        else bs3CpuBasic2_FailedF(a_szName "=" a_szFmt " expected " a_szFmt, (a_Actual), (a_Expected)); \
+    } while (0)
+
+
+/** Indicating that we've got operand size prefix and that it matters. */
+#define BS3CB2SIDTSGDT_F_OPSIZE    UINT8_C(0x01)
+/** Worker requires 386 or later. */
+#define BS3CB2SIDTSGDT_F_386PLUS   UINT8_C(0x02)
+
+
+/*********************************************************************************************************************************
+*   Structures and Typedefs                                                                                                      *
+*********************************************************************************************************************************/
+typedef struct BS3CB2INVLDESCTYPE
+{
+    uint8_t u4Type;
+    uint8_t u1DescType;
+} BS3CB2INVLDESCTYPE;
+
+typedef struct BS3CB2SIDTSGDT
+{
+    const char *pszDesc;
+    FPFNBS3FAR  fpfnWorker;
+    uint8_t     cbInstr;
+    bool        fSs;
+    uint8_t     bMode;
+    uint8_t     fFlags;
+} BS3CB2SIDTSGDT;
+
+
+/*********************************************************************************************************************************
+*   External Symbols                                                                                                             *
+*********************************************************************************************************************************/
+extern FNBS3FAR     bs3CpuBasic2_Int80;
+extern FNBS3FAR     bs3CpuBasic2_Int81;
+extern FNBS3FAR     bs3CpuBasic2_Int82;
+extern FNBS3FAR     bs3CpuBasic2_Int83;
+extern FNBS3FAR     bs3CpuBasic2_ud2;
+#define             g_bs3CpuBasic2_ud2_FlatAddr BS3_DATA_NM(g_bs3CpuBasic2_ud2_FlatAddr)
+extern uint32_t     g_bs3CpuBasic2_ud2_FlatAddr;
+
+extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sidt_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sidt_ss_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sidt_ss_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sidt_rexw_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sidt_opsize_rexw_bx_ud2_c64;
+
+extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_ss_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_ss_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_rexw_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_bx_ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_sgdt_opsize_rexw_bx_ud2_c64;
+
+extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lidt_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt32_es_di__lidt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lidt_opsize_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64;
+
+extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32;
+extern FNBS3FAR     bs3CpuBasic2_lgdt_opsize_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64;
+
+
+
+/*********************************************************************************************************************************
+*   Global Variables                                                                                                             *
+*********************************************************************************************************************************/
+#define                     g_pszTestMode   BS3_CMN_NM(g_pszTestMode)
+static const char BS3_FAR  *g_pszTestMode = (const char *)1;
+#define                     g_bTestMode     BS3_CMN_NM(g_bTestMode)
+static uint8_t              g_bTestMode = 1;
+#define                     g_f16BitSys     BS3_CMN_NM(g_f16BitSys)
+static bool                 g_f16BitSys = 1;
+
+
+/** SIDT test workers. */
+static BS3CB2SIDTSGDT const g_aSidtWorkers[] =
+{
+    { "sidt [bx]",              bs3CpuBasic2_sidt_bx_ud2_c16,             3, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "sidt [ss:bx]",           bs3CpuBasic2_sidt_ss_bx_ud2_c16,          4, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "o32 sidt [bx]",          bs3CpuBasic2_sidt_opsize_bx_ud2_c16,      4, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
+    { "o32 sidt [ss:bx]",       bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c16,   5, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
+    { "sidt [ebx]",             bs3CpuBasic2_sidt_bx_ud2_c32,             3, false,   BS3_MODE_CODE_32, 0 },
+    { "sidt [ss:ebx]",          bs3CpuBasic2_sidt_ss_bx_ud2_c32,          4, true,    BS3_MODE_CODE_32, 0 },
+    { "o16 sidt [ebx]",         bs3CpuBasic2_sidt_opsize_bx_ud2_c32,      4, false,   BS3_MODE_CODE_32, 0 },
+    { "o16 sidt [ss:ebx]",      bs3CpuBasic2_sidt_opsize_ss_bx_ud2_c32,   5, true,    BS3_MODE_CODE_32, 0 },
+    { "sidt [rbx]",             bs3CpuBasic2_sidt_bx_ud2_c64,             3, false,   BS3_MODE_CODE_64, 0 },
+    { "o64 sidt [rbx]",         bs3CpuBasic2_sidt_rexw_bx_ud2_c64,        4, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 sidt [rbx]",         bs3CpuBasic2_sidt_opsize_bx_ud2_c64,      4, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 o64 sidt [rbx]",     bs3CpuBasic2_sidt_opsize_rexw_bx_ud2_c64, 5, false,   BS3_MODE_CODE_64, 0 },
+};
+
+/** SGDT test workers. */
+static BS3CB2SIDTSGDT const g_aSgdtWorkers[] =
+{
+    { "sgdt [bx]",              bs3CpuBasic2_sgdt_bx_ud2_c16,             3, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "sgdt [ss:bx]",           bs3CpuBasic2_sgdt_ss_bx_ud2_c16,          4, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "o32 sgdt [bx]",          bs3CpuBasic2_sgdt_opsize_bx_ud2_c16,      4, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
+    { "o32 sgdt [ss:bx]",       bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c16,   5, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_386PLUS },
+    { "sgdt [ebx]",             bs3CpuBasic2_sgdt_bx_ud2_c32,             3, false,   BS3_MODE_CODE_32, 0 },
+    { "sgdt [ss:ebx]",          bs3CpuBasic2_sgdt_ss_bx_ud2_c32,          4, true,    BS3_MODE_CODE_32, 0 },
+    { "o16 sgdt [ebx]",         bs3CpuBasic2_sgdt_opsize_bx_ud2_c32,      4, false,   BS3_MODE_CODE_32, 0 },
+    { "o16 sgdt [ss:ebx]",      bs3CpuBasic2_sgdt_opsize_ss_bx_ud2_c32,   5, true,    BS3_MODE_CODE_32, 0 },
+    { "sgdt [rbx]",             bs3CpuBasic2_sgdt_bx_ud2_c64,             3, false,   BS3_MODE_CODE_64, 0 },
+    { "o64 sgdt [rbx]",         bs3CpuBasic2_sgdt_rexw_bx_ud2_c64,        4, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 sgdt [rbx]",         bs3CpuBasic2_sgdt_opsize_bx_ud2_c64,      4, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 o64 sgdt [rbx]",     bs3CpuBasic2_sgdt_opsize_rexw_bx_ud2_c64, 5, false,   BS3_MODE_CODE_64, 0 },
+};
+
+/** LIDT test workers. */
+static BS3CB2SIDTSGDT const g_aLidtWorkers[] =
+{
+    { "lidt [bx]",              bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c16,             11, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "lidt [ss:bx]",           bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c16,          12, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "o32 lidt [bx]",          bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c16,      12, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
+    { "o32 lidt [bx]; sidt32",  bs3CpuBasic2_lidt_opsize_bx__sidt32_es_di__lidt_es_si__ud2_c16,    27, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
+    { "o32 lidt [ss:bx]",       bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c16,   13, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
+    { "lidt [ebx]",             bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c32,             11, false,   BS3_MODE_CODE_32, 0 },
+    { "lidt [ss:ebx]",          bs3CpuBasic2_lidt_ss_bx__sidt_es_di__lidt_es_si__ud2_c32,          12, true,    BS3_MODE_CODE_32, 0 },
+    { "o16 lidt [ebx]",         bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c32,      12, false,   BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
+    { "o16 lidt [ss:ebx]",      bs3CpuBasic2_lidt_opsize_ss_bx__sidt_es_di__lidt_es_si__ud2_c32,   13, true,    BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
+    { "lidt [rbx]",             bs3CpuBasic2_lidt_bx__sidt_es_di__lidt_es_si__ud2_c64,              9, false,   BS3_MODE_CODE_64, 0 },
+    { "o64 lidt [rbx]",         bs3CpuBasic2_lidt_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64,        10, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 lidt [rbx]",         bs3CpuBasic2_lidt_opsize_bx__sidt_es_di__lidt_es_si__ud2_c64,      10, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 o64 lidt [rbx]",     bs3CpuBasic2_lidt_opsize_rexw_bx__sidt_es_di__lidt_es_si__ud2_c64, 11, false,   BS3_MODE_CODE_64, 0 },
+};
+
+/** LGDT test workers. */
+static BS3CB2SIDTSGDT const g_aLgdtWorkers[] =
+{
+    { "lgdt [bx]",              bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c16,             11, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "lgdt [ss:bx]",           bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16,          12, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, 0 },
+    { "o32 lgdt [bx]",          bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c16,      12, false,   BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
+    { "o32 lgdt [ss:bx]",       bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c16,   13, true,    BS3_MODE_CODE_16 | BS3_MODE_CODE_V86, BS3CB2SIDTSGDT_F_OPSIZE | BS3CB2SIDTSGDT_F_386PLUS },
+    { "lgdt [ebx]",             bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c32,             11, false,   BS3_MODE_CODE_32, 0 },
+    { "lgdt [ss:ebx]",          bs3CpuBasic2_lgdt_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32,          12, true,    BS3_MODE_CODE_32, 0 },
+    { "o16 lgdt [ebx]",         bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c32,      12, false,   BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
+    { "o16 lgdt [ss:ebx]",      bs3CpuBasic2_lgdt_opsize_ss_bx__sgdt_es_di__lgdt_es_si__ud2_c32,   13, true,    BS3_MODE_CODE_32, BS3CB2SIDTSGDT_F_OPSIZE },
+    { "lgdt [rbx]",             bs3CpuBasic2_lgdt_bx__sgdt_es_di__lgdt_es_si__ud2_c64,              9, false,   BS3_MODE_CODE_64, 0 },
+    { "o64 lgdt [rbx]",         bs3CpuBasic2_lgdt_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64,        10, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 lgdt [rbx]",         bs3CpuBasic2_lgdt_opsize_bx__sgdt_es_di__lgdt_es_si__ud2_c64,      10, false,   BS3_MODE_CODE_64, 0 },
+    { "o32 o64 lgdt [rbx]",     bs3CpuBasic2_lgdt_opsize_rexw_bx__sgdt_es_di__lgdt_es_si__ud2_c64, 11, false,   BS3_MODE_CODE_64, 0 },
+};
+
+
+
+#if 0
+/** Table containing invalid CS selector types. */
+static const BS3CB2INVLDESCTYPE g_aInvalidCsTypes[] =
+{
+    {   X86_SEL_TYPE_RO,            1 },
+    {   X86_SEL_TYPE_RO_ACC,        1 },
+    {   X86_SEL_TYPE_RW,            1 },
+    {   X86_SEL_TYPE_RW_ACC,        1 },
+    {   X86_SEL_TYPE_RO_DOWN,       1 },
+    {   X86_SEL_TYPE_RO_DOWN_ACC,   1 },
+    {   X86_SEL_TYPE_RW_DOWN,       1 },
+    {   X86_SEL_TYPE_RW_DOWN_ACC,   1 },
+    {   0,                          0 },
+    {   1,                          0 },
+    {   2,                          0 },
+    {   3,                          0 },
+    {   4,                          0 },
+    {   5,                          0 },
+    {   6,                          0 },
+    {   7,                          0 },
+    {   8,                          0 },
+    {   9,                          0 },
+    {   10,                         0 },
+    {   11,                         0 },
+    {   12,                         0 },
+    {   13,                         0 },
+    {   14,                         0 },
+    {   15,                         0 },
+};
+
+/** Table containing invalid SS selector types. */
+static const BS3CB2INVLDESCTYPE g_aInvalidSsTypes[] =
+{
+    {   X86_SEL_TYPE_EO,            1 },
+    {   X86_SEL_TYPE_EO_ACC,        1 },
+    {   X86_SEL_TYPE_ER,            1 },
+    {   X86_SEL_TYPE_ER_ACC,        1 },
+    {   X86_SEL_TYPE_EO_CONF,       1 },
+    {   X86_SEL_TYPE_EO_CONF_ACC,   1 },
+    {   X86_SEL_TYPE_ER_CONF,       1 },
+    {   X86_SEL_TYPE_ER_CONF_ACC,   1 },
+    {   0,                          0 },
+    {   1,                          0 },
+    {   2,                          0 },
+    {   3,                          0 },
+    {   4,                          0 },
+    {   5,                          0 },
+    {   6,                          0 },
+    {   7,                          0 },
+    {   8,                          0 },
+    {   9,                          0 },
+    {   10,                         0 },
+    {   11,                         0 },
+    {   12,                         0 },
+    {   13,                         0 },
+    {   14,                         0 },
+    {   15,                         0 },
+};
+#endif
+
+
+
+/**
+ * Wrapper around Bs3TestFailedF that prefixes the error with g_usBs3TestStep
+ * and g_pszTestMode.
+ */
+static void bs3CpuBasic2_FailedF(const char *pszFormat, ...)
+{
+    va_list va;
+
+    char szTmp[168];
+    va_start(va, pszFormat);
+    Bs3StrPrintfV(szTmp, sizeof(szTmp), pszFormat, va);
+    va_end(va);
+
+    Bs3TestFailedF("%u - %s: %s", g_usBs3TestStep, g_pszTestMode, szTmp);
+}
+
+
+#if 0
+/**
+ * Compares trap stuff.
+ */
+static void bs3CpuBasic2_CompareIntCtx1(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint8_t bXcpt)
+{
+    uint16_t const cErrorsBefore = Bs3TestSubErrorCount();
+    CHECK_MEMBER("bXcpt",   "%#04x",    pTrapCtx->bXcpt,        bXcpt);
+    CHECK_MEMBER("bErrCd",  "%#06RX64", pTrapCtx->uErrCd,       0);
+    Bs3TestCheckRegCtxEx(&pTrapCtx->Ctx, pStartCtx, 2 /*int xx*/, 0 /*cbSpAdjust*/, 0 /*fExtraEfl*/, g_pszTestMode, g_usBs3TestStep);
+    if (Bs3TestSubErrorCount() != cErrorsBefore)
+    {
+        Bs3TrapPrintFrame(pTrapCtx);
+#if 1
+        Bs3TestPrintf("Halting: g_uBs3CpuDetected=%#x\n", g_uBs3CpuDetected);
+        Bs3TestPrintf("Halting in CompareTrapCtx1: bXcpt=%#x\n", bXcpt);
+        ASMHalt();
+#endif
+    }
+}
+#endif
+
+
+#if 0
+/**
+ * Compares trap stuff.
+ */
+static void bs3CpuBasic2_CompareTrapCtx2(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t cbIpAdjust,
+                                         uint8_t bXcpt, uint16_t uHandlerCs)
+{
+    uint16_t const cErrorsBefore = Bs3TestSubErrorCount();
+    CHECK_MEMBER("bXcpt",   "%#04x",    pTrapCtx->bXcpt,        bXcpt);
+    CHECK_MEMBER("bErrCd",  "%#06RX64", pTrapCtx->uErrCd,       0);
+    CHECK_MEMBER("uHandlerCs", "%#06x", pTrapCtx->uHandlerCs,   uHandlerCs);
+    Bs3TestCheckRegCtxEx(&pTrapCtx->Ctx, pStartCtx, cbIpAdjust, 0 /*cbSpAdjust*/, 0 /*fExtraEfl*/, g_pszTestMode, g_usBs3TestStep);
+    if (Bs3TestSubErrorCount() != cErrorsBefore)
+    {
+        Bs3TrapPrintFrame(pTrapCtx);
+#if 1
+        Bs3TestPrintf("Halting: g_uBs3CpuDetected=%#x\n", g_uBs3CpuDetected);
+        Bs3TestPrintf("Halting in CompareTrapCtx2: bXcpt=%#x\n", bXcpt);
+        ASMHalt();
+#endif
+    }
+}
+#endif
+
+/**
+ * Compares a CPU trap.
+ */
+static void bs3CpuBasic2_CompareCpuTrapCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t uErrCd,
+                                           uint8_t bXcpt, bool f486ResumeFlagHint)
+{
+    uint16_t const cErrorsBefore = Bs3TestSubErrorCount();
+    uint32_t fExtraEfl;
+
+    CHECK_MEMBER("bXcpt",   "%#04x",    pTrapCtx->bXcpt,        bXcpt);
+    CHECK_MEMBER("bErrCd",  "%#06RX16", (uint16_t)pTrapCtx->uErrCd, (uint16_t)uErrCd); /* 486 only writes a word */
+
+    fExtraEfl = X86_EFL_RF;
+    if (   g_f16BitSys
+        || (   !f486ResumeFlagHint
+            && (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) <= BS3CPU_80486 ) )
+        fExtraEfl = 0;
+    else
+        fExtraEfl = X86_EFL_RF;
+#if 0 /** @todo Running on an AMD Phenom II X6 1100T under AMD-V I'm not getting good X86_EFL_RF results.  Enable this to get on with other work.  */
+    fExtraEfl = pTrapCtx->Ctx.rflags.u32 & X86_EFL_RF;
+#endif
+    Bs3TestCheckRegCtxEx(&pTrapCtx->Ctx, pStartCtx, 0 /*cbIpAdjust*/, 0 /*cbSpAdjust*/, fExtraEfl, g_pszTestMode, g_usBs3TestStep);
+    if (Bs3TestSubErrorCount() != cErrorsBefore)
+    {
+        Bs3TrapPrintFrame(pTrapCtx);
+#if 1
+        Bs3TestPrintf("Halting: g_uBs3CpuDetected=%#x\n", g_uBs3CpuDetected);
+        Bs3TestPrintf("Halting: bXcpt=%#x uErrCd=%#x\n", bXcpt, uErrCd);
+        ASMHalt();
+#endif
+    }
+}
+
+
+/**
+ * Compares \#GP trap.
+ */
+static void bs3CpuBasic2_CompareGpCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t uErrCd)
+{
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, uErrCd, X86_XCPT_GP, true /*f486ResumeFlagHint*/);
+}
+
+#if 0
+/**
+ * Compares \#NP trap.
+ */
+static void bs3CpuBasic2_CompareNpCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t uErrCd)
+{
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, uErrCd, X86_XCPT_NP, true /*f486ResumeFlagHint*/);
+}
+#endif
+
+/**
+ * Compares \#SS trap.
+ */
+static void bs3CpuBasic2_CompareSsCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t uErrCd, bool f486ResumeFlagHint)
+{
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, uErrCd, X86_XCPT_SS, f486ResumeFlagHint);
+}
+
+#if 0
+/**
+ * Compares \#TS trap.
+ */
+static void bs3CpuBasic2_CompareTsCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx, uint16_t uErrCd)
+{
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, uErrCd, X86_XCPT_TS, false /*f486ResumeFlagHint*/);
+}
+#endif
+
+/**
+ * Compares \#PF trap.
+ */
+static void bs3CpuBasic2_ComparePfCtx(PCBS3TRAPFRAME pTrapCtx, PBS3REGCTX pStartCtx, uint16_t uErrCd, uint64_t uCr2Expected)
+{
+    uint64_t const uCr2Saved     = pStartCtx->cr2.u;
+    pStartCtx->cr2.u = uCr2Expected;
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, uErrCd, X86_XCPT_PF, true /*f486ResumeFlagHint*/);
+    pStartCtx->cr2.u = uCr2Saved;
+}
+
+/**
+ * Compares \#UD trap.
+ */
+static void bs3CpuBasic2_CompareUdCtx(PCBS3TRAPFRAME pTrapCtx, PCBS3REGCTX pStartCtx)
+{
+    bs3CpuBasic2_CompareCpuTrapCtx(pTrapCtx, pStartCtx, 0 /*no error code*/, X86_XCPT_UD, true /*f486ResumeFlagHint*/);
+}
+
+
+#if 0 /* convert me */
+static void bs3CpuBasic2_RaiseXcpt1Common(uint16_t const uSysR0Cs, uint16_t const uSysR0CsConf, uint16_t const uSysR0Ss,
+                                          PX86DESC const paIdt, unsigned const cIdteShift)
+{
+    BS3TRAPFRAME    TrapCtx;
+    BS3REGCTX       Ctx80;
+    BS3REGCTX       Ctx81;
+    BS3REGCTX       Ctx82;
+    BS3REGCTX       Ctx83;
+    BS3REGCTX       CtxTmp;
+    BS3REGCTX       CtxTmp2;
+    PBS3REGCTX      apCtx8x[4];
+    unsigned        iCtx;
+    unsigned        iRing;
+    unsigned        iDpl;
+    unsigned        iRpl;
+    unsigned        i, j, k;
+    uint32_t        uExpected;
+    bool const      f486Plus = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80486;
+# if TMPL_BITS == 16
+    bool const      f386Plus = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80386;
+    bool const      f286     = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80286;
+# else
+    bool const      f286     = false;
+    bool const      f386Plus = true;
+    int             rc;
+    uint8_t        *pbIdtCopyAlloc;
+    PX86DESC        pIdtCopy;
+    const unsigned  cbIdte = 1 << (3 + cIdteShift);
+    RTCCUINTXREG    uCr0Saved = ASMGetCR0();
+    RTGDTR          GdtrSaved;
+# endif
+    RTIDTR          IdtrSaved;
+    RTIDTR          Idtr;
+
+    ASMGetIDTR(&IdtrSaved);
+# if TMPL_BITS != 16
+    ASMGetGDTR(&GdtrSaved);
+# endif
+
+    /* make sure they're allocated  */
+    Bs3MemZero(&TrapCtx, sizeof(TrapCtx));
+    Bs3MemZero(&Ctx80, sizeof(Ctx80));
+    Bs3MemZero(&Ctx81, sizeof(Ctx81));
+    Bs3MemZero(&Ctx82, sizeof(Ctx82));
+    Bs3MemZero(&Ctx83, sizeof(Ctx83));
+    Bs3MemZero(&CtxTmp, sizeof(CtxTmp));
+    Bs3MemZero(&CtxTmp2, sizeof(CtxTmp2));
+
+    /* Context array. */
+    apCtx8x[0] = &Ctx80;
+    apCtx8x[1] = &Ctx81;
+    apCtx8x[2] = &Ctx82;
+    apCtx8x[3] = &Ctx83;
+
+# if TMPL_BITS != 16
+    /* Allocate memory for playing around with the IDT. */
+    pbIdtCopyAlloc = NULL;
+    if (BS3_MODE_IS_PAGED(g_bTestMode))
+        pbIdtCopyAlloc = Bs3MemAlloc(BS3MEMKIND_FLAT32, 12*_1K);
+# endif
+
+    /*
+     * IDT entry 80 thru 83 are assigned DPLs according to the number.
+     * (We'll be useing more, but this'll do for now.)
+     */
+    paIdt[0x80 << cIdteShift].Gate.u2Dpl = 0;
+    paIdt[0x81 << cIdteShift].Gate.u2Dpl = 1;
+    paIdt[0x82 << cIdteShift].Gate.u2Dpl = 2;
+    paIdt[0x83 << cIdteShift].Gate.u2Dpl = 3;
+
+    Bs3RegCtxSave(&Ctx80);
+    Ctx80.rsp.u -= 0x300;
+    Ctx80.rip.u  = (uintptr_t)BS3_FP_OFF(&bs3CpuBasic2_Int80);
+# if TMPL_BITS == 16
+    Ctx80.cs = BS3_MODE_IS_RM_OR_V86(g_bTestMode) ? BS3_SEL_TEXT16 : BS3_SEL_R0_CS16;
+# elif TMPL_BITS == 32
+    g_uBs3TrapEipHint = Ctx80.rip.u32;
+# endif
+    Bs3MemCpy(&Ctx81, &Ctx80, sizeof(Ctx80));
+    Ctx81.rip.u  = (uintptr_t)BS3_FP_OFF(&bs3CpuBasic2_Int81);
+    Bs3MemCpy(&Ctx82, &Ctx80, sizeof(Ctx80));
+    Ctx82.rip.u  = (uintptr_t)BS3_FP_OFF(&bs3CpuBasic2_Int82);
+    Bs3MemCpy(&Ctx83, &Ctx80, sizeof(Ctx80));
+    Ctx83.rip.u  = (uintptr_t)BS3_FP_OFF(&bs3CpuBasic2_Int83);
+
+    /*
+     * Check that all the above gates work from ring-0.
+     */
+    for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+    {
+        g_usBs3TestStep = iCtx;
+# if TMPL_BITS == 32
+        g_uBs3TrapEipHint = apCtx8x[iCtx]->rip.u32;
+# endif
+        Bs3TrapSetJmpAndRestore(apCtx8x[iCtx], &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, apCtx8x[iCtx], 0x80+iCtx /*bXcpt*/);
+    }
+
+    /*
+     * Check that the gate DPL checks works.
+     */
+    g_usBs3TestStep = 100;
+    for (iRing = 0; iRing <= 3; iRing++)
+    {
+        for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+        {
+            Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+            Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+# if TMPL_BITS == 32
+            g_uBs3TrapEipHint = CtxTmp.rip.u32;
+# endif
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            if (iCtx < iRing)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+            else
+                bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x80 + iCtx /*bXcpt*/);
+            g_usBs3TestStep++;
+        }
+    }
+
+    /*
+     * Modify the gate CS value and run the handler at a different CPL.
+     * Throw RPL variations into the mix (completely ignored) together
+     * with gate presence.
+     *      1. CPL <= GATE.DPL
+     *      2. GATE.P
+     *      3. GATE.CS.DPL <= CPL (non-conforming segments)
+     */
+    g_usBs3TestStep = 1000;
+    for (i = 0; i <= 3; i++)
+    {
+        for (iRing = 0; iRing <= 3; iRing++)
+        {
+            for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+            {
+# if TMPL_BITS == 32
+                g_uBs3TrapEipHint = apCtx8x[iCtx]->rip.u32;
+# endif
+                Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+                Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+
+                for (j = 0; j <= 3; j++)
+                {
+                    uint16_t const uCs = (uSysR0Cs | j) + (i << BS3_SEL_RING_SHIFT);
+                    for (k = 0; k < 2; k++)
+                    {
+                        g_usBs3TestStep++;
+                        /*Bs3TestPrintf("g_usBs3TestStep=%u iCtx=%u iRing=%u i=%u uCs=%04x\n", g_usBs3TestStep,  iCtx,  iRing, i, uCs);*/
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uCs;
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1Present = k;
+                        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                        /*Bs3TrapPrintFrame(&TrapCtx);*/
+                        if (iCtx < iRing)
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                        else if (k == 0)
+                            bs3CpuBasic2_CompareNpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                        else if (i > iRing)
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, uCs & X86_SEL_MASK_OFF_RPL);
+                        else
+                        {
+                            uint16_t uExpectedCs = uCs & X86_SEL_MASK_OFF_RPL;
+                            if (i <= iCtx && i <= iRing)
+                                uExpectedCs |= i;
+                            bs3CpuBasic2_CompareTrapCtx2(&TrapCtx, &CtxTmp, 2 /*int 8xh*/, 0x80 + iCtx /*bXcpt*/, uExpectedCs);
+                        }
+                    }
+                }
+
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uSysR0Cs;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1Present = 1;
+            }
+        }
+    }
+    BS3_ASSERT(g_usBs3TestStep < 1600);
+
+    /*
+     * Various CS and SS related faults
+     *
+     * We temporarily reconfigure gate 80 and 83 with new CS selectors, the
+     * latter have a CS.DPL of 2 for testing ring transisions and SS loading
+     * without making it impossible to handle faults.
+     */
+    g_usBs3TestStep = 1600;
+    Bs3GdteTestPage00 = Bs3Gdt[uSysR0Cs >> X86_SEL_SHIFT];
+    Bs3GdteTestPage00.Gen.u1Present = 0;
+    Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+    paIdt[0x80 << cIdteShift].Gate.u16Sel = BS3_SEL_TEST_PAGE_00;
+
+    /* CS.PRESENT = 0 */
+    Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+    bs3CpuBasic2_CompareNpCtx(&TrapCtx, &Ctx80, BS3_SEL_TEST_PAGE_00);
+    if (Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+        bs3CpuBasic2_FailedF("selector was accessed");
+    g_usBs3TestStep++;
+
+    /* Check that GATE.DPL is checked before CS.PRESENT. */
+    for (iRing = 1; iRing < 4; iRing++)
+    {
+        Bs3MemCpy(&CtxTmp, &Ctx80, sizeof(CtxTmp));
+        Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, (0x80 << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+        if (Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+            bs3CpuBasic2_FailedF("selector was accessed");
+        g_usBs3TestStep++;
+    }
+
+    /* CS.DPL mismatch takes precedence over CS.PRESENT = 0. */
+    Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+    Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+    bs3CpuBasic2_CompareNpCtx(&TrapCtx, &Ctx80, BS3_SEL_TEST_PAGE_00);
+    if (Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+        bs3CpuBasic2_FailedF("CS selector was accessed");
+    g_usBs3TestStep++;
+    for (iDpl = 1; iDpl < 4; iDpl++)
+    {
+        Bs3GdteTestPage00.Gen.u2Dpl = iDpl;
+        Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx80, BS3_SEL_TEST_PAGE_00);
+        if (Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+            bs3CpuBasic2_FailedF("CS selector was accessed");
+        g_usBs3TestStep++;
+    }
+
+    /* 1608: Check all the invalid CS selector types alone. */
+    Bs3GdteTestPage00 = Bs3Gdt[uSysR0Cs >> X86_SEL_SHIFT];
+    for (i = 0; i < RT_ELEMENTS(g_aInvalidCsTypes); i++)
+    {
+        Bs3GdteTestPage00.Gen.u4Type     = g_aInvalidCsTypes[i].u4Type;
+        Bs3GdteTestPage00.Gen.u1DescType = g_aInvalidCsTypes[i].u1DescType;
+        Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx80, BS3_SEL_TEST_PAGE_00);
+        if (Bs3GdteTestPage00.Gen.u4Type != g_aInvalidCsTypes[i].u4Type)
+            bs3CpuBasic2_FailedF("Invalid CS type %#x/%u -> %#x/%u\n",
+                                 g_aInvalidCsTypes[i].u4Type, g_aInvalidCsTypes[i].u1DescType,
+                                 Bs3GdteTestPage00.Gen.u4Type, Bs3GdteTestPage00.Gen.u1DescType);
+        g_usBs3TestStep++;
+
+        /* Incorrect CS.TYPE takes precedence over CS.PRESENT = 0. */
+        Bs3GdteTestPage00.Gen.u1Present = 0;
+        Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx80, BS3_SEL_TEST_PAGE_00);
+        Bs3GdteTestPage00.Gen.u1Present = 1;
+        g_usBs3TestStep++;
+    }
+
+    /* Fix CS again. */
+    Bs3GdteTestPage00 = Bs3Gdt[uSysR0Cs >> X86_SEL_SHIFT];
+
+    /* 1632: Test SS. */
+    if (!BS3_MODE_IS_64BIT_SYS(g_bTestMode))
+    {
+        uint16_t BS3_FAR *puTssSs2    = BS3_MODE_IS_16BIT_SYS(g_bTestMode) ? &Bs3Tss16.ss2 : &Bs3Tss32.ss2;
+        uint16_t const    uSavedSs2   = *puTssSs2;
+        X86DESC const     SavedGate83 = paIdt[0x83 << cIdteShift];
+
+        /* Make the handler execute in ring-2. */
+        Bs3GdteTestPage02 = Bs3Gdt[(uSysR0Cs + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        Bs3GdteTestPage02.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        paIdt[0x83 << cIdteShift].Gate.u16Sel = BS3_SEL_TEST_PAGE_02 | 2;
+
+        Bs3MemCpy(&CtxTmp, &Ctx83, sizeof(CtxTmp));
+        Bs3RegCtxConvertToRingX(&CtxTmp, 3); /* yeah, from 3 so SS:xSP is reloaded. */
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83);
+        if (!(Bs3GdteTestPage02.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+            bs3CpuBasic2_FailedF("CS selector was not access");
+        g_usBs3TestStep++;
+
+        /* Create a SS.DPL=2 stack segment and check that SS2.RPL matters and
+           that we get #SS if the selector isn't present. */
+        i = 0; /* used for cycling thru invalid CS types */
+        for (k = 0; k < 10; k++)
+        {
+            /* k=0: present,
+               k=1: not-present,
+               k=2: present but very low limit,
+               k=3: not-present, low limit.
+               k=4: present, read-only.
+               k=5: not-present, read-only.
+               k=6: present, code-selector.
+               k=7: not-present, code-selector.
+               k=8: present, read-write / no access + system (=LDT).
+               k=9: not-present, read-write / no access + system (=LDT).
+               */
+            Bs3GdteTestPage03 = Bs3Gdt[(uSysR0Ss + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+            Bs3GdteTestPage03.Gen.u1Present  = !(k & 1);
+            if (k >= 8)
+            {
+                Bs3GdteTestPage03.Gen.u1DescType = 0; /* system */
+                Bs3GdteTestPage03.Gen.u4Type = X86_SEL_TYPE_RW; /* = LDT */
+            }
+            else if (k >= 6)
+                Bs3GdteTestPage03.Gen.u4Type = X86_SEL_TYPE_ER;
+            else if (k >= 4)
+                Bs3GdteTestPage03.Gen.u4Type = X86_SEL_TYPE_RO;
+            else if (k >= 2)
+            {
+                Bs3GdteTestPage03.Gen.u16LimitLow   = 0x400;
+                Bs3GdteTestPage03.Gen.u4LimitHigh   = 0;
+                Bs3GdteTestPage03.Gen.u1Granularity = 0;
+            }
+
+            for (iDpl = 0; iDpl < 4; iDpl++)
+            {
+                Bs3GdteTestPage03.Gen.u2Dpl = iDpl;
+
+                for (iRpl = 0; iRpl < 4; iRpl++)
+                {
+                    *puTssSs2 = BS3_SEL_TEST_PAGE_03 | iRpl;
+                    //Bs3TestPrintf("k=%u iDpl=%u iRpl=%u step=%u\n", k, iDpl, iRpl, g_usBs3TestStep);
+                    Bs3GdteTestPage02.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+                    Bs3GdteTestPage03.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    if (iRpl != 2 || iRpl != iDpl || k >= 4)
+                        bs3CpuBasic2_CompareTsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03);
+                    else if (k != 0)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03,
+                                                  k == 2 /*f486ResumeFlagHint*/);
+                    else
+                    {
+                        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83);
+                        if (TrapCtx.uHandlerSs != (BS3_SEL_TEST_PAGE_03 | 2))
+                            bs3CpuBasic2_FailedF("uHandlerSs=%#x expected %#x\n", TrapCtx.uHandlerSs, BS3_SEL_TEST_PAGE_03 | 2);
+                    }
+                    if (!(Bs3GdteTestPage02.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                        bs3CpuBasic2_FailedF("CS selector was not access");
+                    if (   TrapCtx.bXcpt == 0x83
+                        || (TrapCtx.bXcpt == X86_XCPT_SS && k == 2) )
+                    {
+                        if (!(Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                            bs3CpuBasic2_FailedF("SS selector was not accessed");
+                    }
+                    else if (Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+                        bs3CpuBasic2_FailedF("SS selector was accessed");
+                    g_usBs3TestStep++;
+
+                    /* +1: Modify the gate DPL to check that this is checked before SS.DPL and SS.PRESENT. */
+                    paIdt[0x83 << cIdteShift].Gate.u2Dpl = 2;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, (0x83 << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                    paIdt[0x83 << cIdteShift].Gate.u2Dpl = 3;
+                    g_usBs3TestStep++;
+
+                    /* +2: Check the the CS.DPL check is done before the SS ones. Restoring the
+                           ring-0 INT 83 context triggers the CS.DPL < CPL check. */
+                    Bs3TrapSetJmpAndRestore(&Ctx83, &TrapCtx);
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx83, BS3_SEL_TEST_PAGE_02);
+                    g_usBs3TestStep++;
+
+                    /* +3: Now mark the CS selector not present and check that that also triggers before SS stuff. */
+                    Bs3GdteTestPage02.Gen.u1Present = 0;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    bs3CpuBasic2_CompareNpCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_02);
+                    Bs3GdteTestPage02.Gen.u1Present = 1;
+                    g_usBs3TestStep++;
+
+                    /* +4: Make the CS selector some invalid type and check it triggers before SS stuff. */
+                    Bs3GdteTestPage02.Gen.u4Type = g_aInvalidCsTypes[i].u4Type;
+                    Bs3GdteTestPage02.Gen.u1DescType = g_aInvalidCsTypes[i].u1DescType;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_02);
+                    Bs3GdteTestPage02.Gen.u4Type = X86_SEL_TYPE_ER_ACC;
+                    Bs3GdteTestPage02.Gen.u1DescType = 1;
+                    g_usBs3TestStep++;
+
+                    /* +5: Now, make the CS selector limit too small and that it triggers after SS trouble.
+                           The 286 had a simpler approach to these GP(0). */
+                    Bs3GdteTestPage02.Gen.u16LimitLow = 0;
+                    Bs3GdteTestPage02.Gen.u4LimitHigh = 0;
+                    Bs3GdteTestPage02.Gen.u1Granularity = 0;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    if (f286)
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, 0 /*uErrCd*/);
+                    else if (iRpl != 2 || iRpl != iDpl || k >= 4)
+                        bs3CpuBasic2_CompareTsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03);
+                    else if (k != 0)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03, k == 2 /*f486ResumeFlagHint*/);
+                    else
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, 0 /*uErrCd*/);
+                    Bs3GdteTestPage02 = Bs3Gdt[(uSysR0Cs + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+                    g_usBs3TestStep++;
+                }
+            }
+        }
+
+        /* Check all the invalid SS selector types alone. */
+        Bs3GdteTestPage02 = Bs3Gdt[(uSysR0Cs + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        Bs3GdteTestPage03 = Bs3Gdt[(uSysR0Ss + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        *puTssSs2 = BS3_SEL_TEST_PAGE_03 | 2;
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83);
+        g_usBs3TestStep++;
+        for (i = 0; i < RT_ELEMENTS(g_aInvalidSsTypes); i++)
+        {
+            Bs3GdteTestPage03.Gen.u4Type     = g_aInvalidSsTypes[i].u4Type;
+            Bs3GdteTestPage03.Gen.u1DescType = g_aInvalidSsTypes[i].u1DescType;
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            bs3CpuBasic2_CompareTsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03);
+            if (Bs3GdteTestPage03.Gen.u4Type != g_aInvalidSsTypes[i].u4Type)
+                bs3CpuBasic2_FailedF("Invalid SS type %#x/%u -> %#x/%u\n",
+                                     g_aInvalidSsTypes[i].u4Type, g_aInvalidSsTypes[i].u1DescType,
+                                     Bs3GdteTestPage03.Gen.u4Type, Bs3GdteTestPage03.Gen.u1DescType);
+            g_usBs3TestStep++;
+        }
+
+        /*
+         * Continue the SS experiments with a expand down segment.  We'll use
+         * the same setup as we already have with gate 83h being DPL and
+         * having CS.DPL=2.
+         *
+         * Expand down segments are weird. The valid area is practically speaking
+         * reversed.  So, a 16-bit segment with a limit of 0x6000 will have valid
+         * addresses from 0xffff thru 0x6001.
+         *
+         * So, with expand down segments we can more easily cut partially into the
+         * pushing of the iret frame and trigger more interesting behavior than
+         * with regular "expand up" segments where the whole pushing area is either
+         * all fine or not not fine.
+         */
+        Bs3GdteTestPage02 = Bs3Gdt[(uSysR0Cs + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        Bs3GdteTestPage03 = Bs3Gdt[(uSysR0Ss + (2 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        Bs3GdteTestPage03.Gen.u2Dpl = 2;
+        Bs3GdteTestPage03.Gen.u4Type = X86_SEL_TYPE_RW_DOWN;
+        *puTssSs2 = BS3_SEL_TEST_PAGE_03 | 2;
+
+        /* First test, limit = max --> no bytes accessible --> #GP */
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03, true /*f486ResumeFlagHint*/);
+
+        /* Second test, limit = 0 --> all by zero byte accessible --> works */
+        Bs3GdteTestPage03.Gen.u16LimitLow = 0;
+        Bs3GdteTestPage03.Gen.u4LimitHigh = 0;
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83);
+
+        /* Modify the gate handler to be a dummy that immediately does UD2
+           and triggers #UD, then advance the limit down till we get the #UD. */
+        Bs3GdteTestPage03.Gen.u1Granularity = 0;
+
+        Bs3MemCpy(&CtxTmp2, &CtxTmp, sizeof(CtxTmp2));  /* #UD result context */
+        if (g_f16BitSys)
+        {
+            CtxTmp2.rip.u = g_bs3CpuBasic2_ud2_FlatAddr - BS3_ADDR_BS3TEXT16;
+            Bs3Trap16SetGate(0x83, X86_SEL_TYPE_SYS_286_INT_GATE, 3, BS3_SEL_TEST_PAGE_02, CtxTmp2.rip.u16, 0 /*cParams*/);
+            CtxTmp2.rsp.u = Bs3Tss16.sp2 - 2*5;
+        }
+        else
+        {
+            CtxTmp2.rip.u = g_bs3CpuBasic2_ud2_FlatAddr;
+            Bs3Trap32SetGate(0x83, X86_SEL_TYPE_SYS_386_INT_GATE, 3, BS3_SEL_TEST_PAGE_02, CtxTmp2.rip.u32, 0 /*cParams*/);
+            CtxTmp2.rsp.u = Bs3Tss32.esp2 - 4*5;
+        }
+        CtxTmp2.bMode = g_bTestMode; /* g_bBs3CurrentMode not changed by the UD2 handler. */
+        CtxTmp2.cs = BS3_SEL_TEST_PAGE_02 | 2;
+        CtxTmp2.ss = BS3_SEL_TEST_PAGE_03 | 2;
+        CtxTmp2.bCpl = 2;
+
+        /* test run. */
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxTmp2);
+        g_usBs3TestStep++;
+
+        /* Real run. */
+        i = (g_f16BitSys ? 2 : 4) * 6 + 1;
+        while (i-- > 0)
+        {
+            Bs3GdteTestPage03.Gen.u16LimitLow = CtxTmp2.rsp.u16 + i - 1;
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            if (i > 0)
+                bs3CpuBasic2_CompareSsCtx(&TrapCtx, &CtxTmp, BS3_SEL_TEST_PAGE_03, true /*f486ResumeFlagHint*/);
+            else
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxTmp2);
+            g_usBs3TestStep++;
+        }
+
+        /* Do a run where we do the same-ring kind of access.  */
+        Bs3RegCtxConvertToRingX(&CtxTmp, 2);
+        if (g_f16BitSys)
+        {
+            CtxTmp2.rsp.u32 = CtxTmp.rsp.u32 - 2*3;
+            i = 2*3 - 1;
+        }
+        else
+        {
+            CtxTmp2.rsp.u32 = CtxTmp.rsp.u32 - 4*3;
+            i = 4*3 - 1;
+        }
+        CtxTmp.ss = BS3_SEL_TEST_PAGE_03 | 2;
+        CtxTmp2.ds = CtxTmp.ds;
+        CtxTmp2.es = CtxTmp.es;
+        CtxTmp2.fs = CtxTmp.fs;
+        CtxTmp2.gs = CtxTmp.gs;
+        while (i-- > 0)
+        {
+            Bs3GdteTestPage03.Gen.u16LimitLow = CtxTmp2.rsp.u16 + i - 1;
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            if (i > 0)
+                bs3CpuBasic2_CompareSsCtx(&TrapCtx, &CtxTmp, 0 /*BS3_SEL_TEST_PAGE_03*/, true /*f486ResumeFlagHint*/);
+            else
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxTmp2);
+            g_usBs3TestStep++;
+        }
+
+        *puTssSs2 = uSavedSs2;
+        paIdt[0x83 << cIdteShift] = SavedGate83;
+    }
+    paIdt[0x80 << cIdteShift].Gate.u16Sel = uSysR0Cs;
+    BS3_ASSERT(g_usBs3TestStep < 3000);
+
+    /*
+     * Modify the gate CS value with a conforming segment.
+     */
+    g_usBs3TestStep = 3000;
+    for (i = 0; i <= 3; i++) /* cs.dpl */
+    {
+        for (iRing = 0; iRing <= 3; iRing++)
+        {
+            for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+            {
+                Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+                Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+# if TMPL_BITS == 32
+                g_uBs3TrapEipHint = CtxTmp.rip.u32;
+# endif
+
+                for (j = 0; j <= 3; j++) /* rpl */
+                {
+                    uint16_t const uCs = (uSysR0CsConf | j) + (i << BS3_SEL_RING_SHIFT);
+                    /*Bs3TestPrintf("g_usBs3TestStep=%u iCtx=%u iRing=%u i=%u uCs=%04x\n", g_usBs3TestStep,  iCtx,  iRing, i, uCs);*/
+                    paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uCs;
+                    Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                    //Bs3TestPrintf("%u/%u/%u/%u: cs=%04x hcs=%04x xcpt=%02x\n", i, iRing, iCtx, j, uCs, TrapCtx.uHandlerCs, TrapCtx.bXcpt);
+                    /*Bs3TrapPrintFrame(&TrapCtx);*/
+                    g_usBs3TestStep++;
+                    if (iCtx < iRing)
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                    else if (i > iRing)
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, uCs & X86_SEL_MASK_OFF_RPL);
+                    else
+                        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x80 + iCtx /*bXcpt*/);
+                }
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uSysR0Cs;
+            }
+        }
+    }
+    BS3_ASSERT(g_usBs3TestStep < 3500);
+
+    /*
+     * The gates must be 64-bit in long mode.
+     */
+    if (cIdteShift != 0)
+    {
+        g_usBs3TestStep = 3500;
+        for (i = 0; i <= 3; i++)
+        {
+            for (iRing = 0; iRing <= 3; iRing++)
+            {
+                for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+                {
+                    Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+                    Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+
+                    for (j = 0; j < 2; j++)
+                    {
+                        static const uint16_t s_auCSes[2] = { BS3_SEL_R0_CS16, BS3_SEL_R0_CS32 };
+                        uint16_t uCs = (s_auCSes[j] | i) + (i << BS3_SEL_RING_SHIFT);
+                        g_usBs3TestStep++;
+                        /*Bs3TestPrintf("g_usBs3TestStep=%u iCtx=%u iRing=%u i=%u uCs=%04x\n", g_usBs3TestStep,  iCtx,  iRing, i, uCs);*/
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uCs;
+                        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                        /*Bs3TrapPrintFrame(&TrapCtx);*/
+                        if (iCtx < iRing)
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                        else
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, uCs & X86_SEL_MASK_OFF_RPL);
+                    }
+                    paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uSysR0Cs;
+                }
+            }
+        }
+        BS3_ASSERT(g_usBs3TestStep < 4000);
+    }
+
+    /*
+     * IDT limit check.  The 286 does not access X86DESCGATE::u16OffsetHigh.
+     */
+    g_usBs3TestStep = 5000;
+    i = (0x80 << (cIdteShift + 3)) - 1;
+    j = (0x82 << (cIdteShift + 3)) - (!f286 ? 1 : 3);
+    k = (0x83 << (cIdteShift + 3)) - 1;
+    for (; i <= k; i++, g_usBs3TestStep++)
+    {
+        Idtr = IdtrSaved;
+        Idtr.cbIdt  = i;
+        ASMSetIDTR(&Idtr);
+        Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+        if (i < j)
+            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx81, (0x81 << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+        else
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx81, 0x81 /*bXcpt*/);
+    }
+    ASMSetIDTR(&IdtrSaved);
+    BS3_ASSERT(g_usBs3TestStep < 5100);
+
+# if TMPL_BITS != 16 /* Only do the paging related stuff in 32-bit and 64-bit modes. */
+
+    /*
+     * IDT page not present. Placing the IDT copy such that 0x80 is on the
+     * first page and 0x81 is on the second page.  We need proceed to move
+     * it down byte by byte to check that any inaccessible byte means #PF.
+     *
+     * Note! We must reload the alternative IDTR for each run as any kind of
+     *       printing to the string (like error reporting) will cause a switch
+     *       to real mode and back, reloading the default IDTR.
+     */
+    g_usBs3TestStep = 5200;
+    if (BS3_MODE_IS_PAGED(g_bTestMode) && pbIdtCopyAlloc)
+    {
+        uint32_t const uCr2Expected = Bs3SelPtrToFlat(pbIdtCopyAlloc) + _4K;
+        for (j = 0; j < cbIdte; j++)
+        {
+            pIdtCopy = (PX86DESC)&pbIdtCopyAlloc[_4K - cbIdte * 0x81 - j];
+            Bs3MemCpy(pIdtCopy, paIdt, cbIdte * 256);
+
+            Idtr.cbIdt = IdtrSaved.cbIdt;
+            Idtr.pIdt  = Bs3SelPtrToFlat(pIdtCopy);
+
+            ASMSetIDTR(&Idtr);
+            Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx81, 0x81 /*bXcpt*/);
+            g_usBs3TestStep++;
+
+            ASMSetIDTR(&Idtr);
+            Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx80, 0x80 /*bXcpt*/);
+            g_usBs3TestStep++;
+
+            rc = Bs3PagingProtect(uCr2Expected, _4K, 0 /*fSet*/, X86_PTE_P /*fClear*/);
+            if (RT_SUCCESS(rc))
+            {
+                ASMSetIDTR(&Idtr);
+                Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+                bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx80, 0x80 /*bXcpt*/);
+                g_usBs3TestStep++;
+
+                ASMSetIDTR(&Idtr);
+                Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+                if (f486Plus)
+                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx81, 0 /*uErrCd*/, uCr2Expected);
+                else
+                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx81, X86_TRAP_PF_RW /*uErrCd*/, uCr2Expected + 4 - RT_MIN(j, 4));
+                g_usBs3TestStep++;
+
+                Bs3PagingProtect(uCr2Expected, _4K, X86_PTE_P /*fSet*/, 0 /*fClear*/);
+
+                /* Check if that the entry type is checked after the whole IDTE has been cleared for #PF. */
+                pIdtCopy[0x80 << cIdteShift].Gate.u4Type = 0;
+                rc = Bs3PagingProtect(uCr2Expected, _4K, 0 /*fSet*/, X86_PTE_P /*fClear*/);
+                if (RT_SUCCESS(rc))
+                {
+                    ASMSetIDTR(&Idtr);
+                    Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+                    if (f486Plus)
+                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx81, 0 /*uErrCd*/, uCr2Expected);
+                    else
+                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx81, X86_TRAP_PF_RW /*uErrCd*/, uCr2Expected + 4 - RT_MIN(j, 4));
+                    g_usBs3TestStep++;
+
+                    Bs3PagingProtect(uCr2Expected, _4K, X86_PTE_P /*fSet*/, 0 /*fClear*/);
+                }
+            }
+            else
+                Bs3TestPrintf("Bs3PagingProtectPtr: %d\n", i);
+
+            ASMSetIDTR(&IdtrSaved);
+        }
+    }
+
+    /*
+     * The read/write and user/supervisor bits the IDT PTEs are irrelevant.
+     */
+    g_usBs3TestStep = 5300;
+    if (BS3_MODE_IS_PAGED(g_bTestMode) && pbIdtCopyAlloc)
+    {
+        Bs3MemCpy(pbIdtCopyAlloc, paIdt, cbIdte * 256);
+        Idtr.cbIdt = IdtrSaved.cbIdt;
+        Idtr.pIdt  = Bs3SelPtrToFlat(pbIdtCopyAlloc);
+
+        ASMSetIDTR(&Idtr);
+        Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx81, 0x81 /*bXcpt*/);
+        g_usBs3TestStep++;
+
+        rc = Bs3PagingProtect(Idtr.pIdt, _4K, 0 /*fSet*/, X86_PTE_RW | X86_PTE_US /*fClear*/);
+        if (RT_SUCCESS(rc))
+        {
+            ASMSetIDTR(&Idtr);
+            Bs3TrapSetJmpAndRestore(&Ctx81, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx81, 0x81 /*bXcpt*/);
+            g_usBs3TestStep++;
+
+            Bs3PagingProtect(Idtr.pIdt, _4K, X86_PTE_RW | X86_PTE_US /*fSet*/, 0 /*fClear*/);
+        }
+        ASMSetIDTR(&IdtrSaved);
+    }
+
+    /*
+     * Check that CS.u1Accessed is set to 1. Use the test page selector #0 and #3 together
+     * with interrupt gates 80h and 83h, respectively.
+     */
+/** @todo Throw in SS.u1Accessed too. */
+    g_usBs3TestStep = 5400;
+    if (BS3_MODE_IS_PAGED(g_bTestMode) && pbIdtCopyAlloc)
+    {
+        Bs3GdteTestPage00 = Bs3Gdt[uSysR0Cs >> X86_SEL_SHIFT];
+        Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        paIdt[0x80 << cIdteShift].Gate.u16Sel   = BS3_SEL_TEST_PAGE_00;
+
+        Bs3GdteTestPage03 = Bs3Gdt[(uSysR0Cs + (3 << BS3_SEL_RING_SHIFT)) >> X86_SEL_SHIFT];
+        Bs3GdteTestPage03.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        paIdt[0x83 << cIdteShift].Gate.u16Sel   = BS3_SEL_TEST_PAGE_03; /* rpl is ignored, so leave it as zero. */
+
+        /* Check that the CS.A bit is being set on a general basis and that
+           the special CS values work with out generic handler code. */
+        Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx80, 0x80 /*bXcpt*/);
+        if (!(Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+            bs3CpuBasic2_FailedF("u4Type=%#x, not accessed", Bs3GdteTestPage00.Gen.u4Type);
+        g_usBs3TestStep++;
+
+        Bs3MemCpy(&CtxTmp, &Ctx83, sizeof(CtxTmp));
+        Bs3RegCtxConvertToRingX(&CtxTmp, 3);
+        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+        bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83 /*bXcpt*/);
+        if (!(Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+            bs3CpuBasic2_FailedF("u4Type=%#x, not accessed!", Bs3GdteTestPage00.Gen.u4Type);
+        if (TrapCtx.uHandlerCs != (BS3_SEL_TEST_PAGE_03 | 3))
+            bs3CpuBasic2_FailedF("uHandlerCs=%#x, expected %#x", TrapCtx.uHandlerCs, (BS3_SEL_TEST_PAGE_03 | 3));
+        g_usBs3TestStep++;
+
+        /*
+         * Now check that setting CS.u1Access to 1 does __NOT__ trigger a page
+         * fault due to the RW bit being zero.
+         * (We check both with with and without the WP bit if 80486.)
+         */
+        if ((g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80486)
+            ASMSetCR0(uCr0Saved | X86_CR0_WP);
+
+        Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        Bs3GdteTestPage03.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        rc = Bs3PagingProtect(GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00, 8, 0 /*fSet*/, X86_PTE_RW /*fClear*/);
+        if (RT_SUCCESS(rc))
+        {
+            /* ring-0 handler */
+            Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx80, 0x80 /*bXcpt*/);
+            if (!(Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                bs3CpuBasic2_FailedF("u4Type=%#x, not accessed!", Bs3GdteTestPage00.Gen.u4Type);
+            g_usBs3TestStep++;
+
+            /* ring-3 handler */
+            Bs3MemCpy(&CtxTmp, &Ctx83, sizeof(CtxTmp));
+            Bs3RegCtxConvertToRingX(&CtxTmp, 3);
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83 /*bXcpt*/);
+            if (!(Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                bs3CpuBasic2_FailedF("u4Type=%#x, not accessed!", Bs3GdteTestPage00.Gen.u4Type);
+            g_usBs3TestStep++;
+
+            /* clear WP and repeat the above. */
+            if ((g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80486)
+                ASMSetCR0(uCr0Saved & ~X86_CR0_WP);
+            Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED; /* (No need to RW the page - ring-0, WP=0.) */
+            Bs3GdteTestPage03.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED; /* (No need to RW the page - ring-0, WP=0.) */
+
+            Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &Ctx80, 0x80 /*bXcpt*/);
+            if (!(Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                bs3CpuBasic2_FailedF("u4Type=%#x, not accessed!", Bs3GdteTestPage00.Gen.u4Type);
+            g_usBs3TestStep++;
+
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x83 /*bXcpt*/);
+            if (!(Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED))
+                bs3CpuBasic2_FailedF("u4Type=%#x, not accessed!n", Bs3GdteTestPage03.Gen.u4Type);
+            g_usBs3TestStep++;
+
+            Bs3PagingProtect(GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00, 8, X86_PTE_RW /*fSet*/, 0 /*fClear*/);
+        }
+
+        ASMSetCR0(uCr0Saved);
+
+        /*
+         * While we're here, check that if the CS GDT entry is a non-present
+         * page we do get a #PF with the rigth error code and CR2.
+         */
+        Bs3GdteTestPage00.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED; /* Just for fun, really a pointless gesture. */
+        Bs3GdteTestPage03.Gen.u4Type &= ~X86_SEL_TYPE_ACCESSED;
+        rc = Bs3PagingProtect(GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00, 8, 0 /*fSet*/, X86_PTE_P /*fClear*/);
+        if (RT_SUCCESS(rc))
+        {
+            Bs3TrapSetJmpAndRestore(&Ctx80, &TrapCtx);
+            if (f486Plus)
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx80, 0 /*uErrCd*/, GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00);
+            else
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx80, X86_TRAP_PF_RW, GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00 + 4);
+            g_usBs3TestStep++;
+
+            /* Do it from ring-3 to check ErrCd, which doesn't set X86_TRAP_PF_US it turns out. */
+            Bs3MemCpy(&CtxTmp, &Ctx83, sizeof(CtxTmp));
+            Bs3RegCtxConvertToRingX(&CtxTmp, 3);
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+
+            if (f486Plus)
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &CtxTmp, 0 /*uErrCd*/, GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_03);
+            else
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &CtxTmp, X86_TRAP_PF_RW, GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_03 + 4);
+            g_usBs3TestStep++;
+
+            Bs3PagingProtect(GdtrSaved.pGdt + BS3_SEL_TEST_PAGE_00, 8, X86_PTE_P /*fSet*/, 0 /*fClear*/);
+            if (Bs3GdteTestPage00.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+                bs3CpuBasic2_FailedF("u4Type=%#x, accessed! #1", Bs3GdteTestPage00.Gen.u4Type);
+            if (Bs3GdteTestPage03.Gen.u4Type & X86_SEL_TYPE_ACCESSED)
+                bs3CpuBasic2_FailedF("u4Type=%#x, accessed! #2", Bs3GdteTestPage03.Gen.u4Type);
+        }
+
+        /* restore */
+        paIdt[0x80 << cIdteShift].Gate.u16Sel = uSysR0Cs;
+        paIdt[0x83 << cIdteShift].Gate.u16Sel = uSysR0Cs;// + (3 << BS3_SEL_RING_SHIFT) + 3;
+    }
+
+# endif /* 32 || 64*/
+
+    /*
+     * Check broad EFLAGS effects.
+     */
+    g_usBs3TestStep = 5600;
+    for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+    {
+        for (iRing = 0; iRing < 4; iRing++)
+        {
+            Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+            Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+
+            /* all set */
+            CtxTmp.rflags.u32 &= X86_EFL_VM | X86_EFL_1;
+            CtxTmp.rflags.u32 |= X86_EFL_CF | X86_EFL_PF | X86_EFL_AF | X86_EFL_ZF | X86_EFL_SF /* | X86_EFL_TF */ /*| X86_EFL_IF*/
+                               | X86_EFL_DF | X86_EFL_OF | X86_EFL_IOPL /* | X86_EFL_NT*/;
+            if (f486Plus)
+                CtxTmp.rflags.u32 |= X86_EFL_AC;
+            if (f486Plus && !g_f16BitSys)
+                CtxTmp.rflags.u32 |= X86_EFL_RF;
+            if (g_uBs3CpuDetected & BS3CPU_F_CPUID)
+                CtxTmp.rflags.u32 |= X86_EFL_VIF | X86_EFL_VIP;
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            CtxTmp.rflags.u32 &= ~X86_EFL_RF;
+
+            if (iCtx >= iRing)
+                bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x80 + iCtx /*bXcpt*/);
+            else
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+            uExpected = CtxTmp.rflags.u32
+                      & (  X86_EFL_1 |  X86_EFL_CF | X86_EFL_PF | X86_EFL_AF | X86_EFL_ZF | X86_EFL_SF | X86_EFL_DF
+                         | X86_EFL_OF | X86_EFL_IOPL | X86_EFL_NT | X86_EFL_VM | X86_EFL_AC | X86_EFL_VIF | X86_EFL_VIP
+                         | X86_EFL_ID /*| X86_EFL_TF*/ /*| X86_EFL_IF*/ /*| X86_EFL_RF*/ );
+            if (TrapCtx.fHandlerRfl != uExpected)
+                bs3CpuBasic2_FailedF("unexpected handler rflags value: %RX64 expected %RX32; CtxTmp.rflags=%RX64 Ctx.rflags=%RX64\n",
+                                     TrapCtx.fHandlerRfl, uExpected, CtxTmp.rflags.u, TrapCtx.Ctx.rflags.u);
+            g_usBs3TestStep++;
+
+            /* all cleared */
+            if ((g_uBs3CpuDetected & BS3CPU_TYPE_MASK) < BS3CPU_80286)
+                CtxTmp.rflags.u32 = apCtx8x[iCtx]->rflags.u32 & (X86_EFL_RA1_MASK | UINT16_C(0xf000));
+            else
+                CtxTmp.rflags.u32 = apCtx8x[iCtx]->rflags.u32 & (X86_EFL_VM | X86_EFL_RA1_MASK);
+            Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+            if (iCtx >= iRing)
+                bs3CpuBasic2_CompareIntCtx1(&TrapCtx, &CtxTmp, 0x80 + iCtx /*bXcpt*/);
+            else
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+            uExpected = CtxTmp.rflags.u32;
+            if (TrapCtx.fHandlerRfl != uExpected)
+                bs3CpuBasic2_FailedF("unexpected handler rflags value: %RX64 expected %RX32; CtxTmp.rflags=%RX64 Ctx.rflags=%RX64\n",
+                                     TrapCtx.fHandlerRfl, uExpected, CtxTmp.rflags.u, TrapCtx.Ctx.rflags.u);
+            g_usBs3TestStep++;
+        }
+    }
+
+/** @todo CS.LIMIT / canonical(CS)  */
+
+
+    /*
+     * Check invalid gate types.
+     */
+    g_usBs3TestStep = 32000;
+    for (iRing = 0; iRing <= 3; iRing++)
+    {
+        static const uint16_t   s_auCSes[]        = { BS3_SEL_R0_CS16, BS3_SEL_R0_CS32, BS3_SEL_R0_CS64,
+                                                      BS3_SEL_TSS16, BS3_SEL_TSS32, BS3_SEL_TSS64, 0, BS3_SEL_SPARE_1f };
+        static uint16_t const   s_auInvlTypes64[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
+                                                      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+                                                      0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f };
+        static uint16_t const   s_auInvlTypes32[] = { 0, 1, 2, 3, 8, 9, 10, 11, 13,
+                                                      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+                                                      0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+                                                      /*286:*/ 12, 14, 15 };
+        uint16_t const * const  pauInvTypes       = cIdteShift != 0 ? s_auInvlTypes64 : s_auInvlTypes32;
+        uint16_t const          cInvTypes         = cIdteShift != 0 ? RT_ELEMENTS(s_auInvlTypes64)
+                                                  : f386Plus ? RT_ELEMENTS(s_auInvlTypes32) - 3 : RT_ELEMENTS(s_auInvlTypes32);
+
+
+        for (iCtx = 0; iCtx < RT_ELEMENTS(apCtx8x); iCtx++)
+        {
+            unsigned iType;
+
+            Bs3MemCpy(&CtxTmp, apCtx8x[iCtx], sizeof(CtxTmp));
+            Bs3RegCtxConvertToRingX(&CtxTmp, iRing);
+# if TMPL_BITS == 32
+            g_uBs3TrapEipHint = CtxTmp.rip.u32;
+# endif
+            for (iType = 0; iType < cInvTypes; iType++)
+            {
+                uint8_t const bSavedType = paIdt[(0x80 + iCtx) << cIdteShift].Gate.u4Type;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1DescType = pauInvTypes[iType] >> 4;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u4Type     = pauInvTypes[iType] & 0xf;
+
+                for (i = 0; i < 4; i++)
+                {
+                    for (j = 0; j < RT_ELEMENTS(s_auCSes); j++)
+                    {
+                        uint16_t uCs = (unsigned)(s_auCSes[j] - BS3_SEL_R0_FIRST) < (unsigned)(4 << BS3_SEL_RING_SHIFT)
+                                     ? (s_auCSes[j] | i) + (i << BS3_SEL_RING_SHIFT)
+                                     : s_auCSes[j] | i;
+                        /*Bs3TestPrintf("g_usBs3TestStep=%u iCtx=%u iRing=%u i=%u uCs=%04x type=%#x\n", g_usBs3TestStep, iCtx, iRing, i, uCs, pauInvTypes[iType]);*/
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel = uCs;
+                        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                        g_usBs3TestStep++;
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+
+                        /* Mark it not-present to check that invalid type takes precedence. */
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1Present = 0;
+                        Bs3TrapSetJmpAndRestore(&CtxTmp, &TrapCtx);
+                        g_usBs3TestStep++;
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &CtxTmp, ((0x80 + iCtx) << X86_TRAP_ERR_SEL_SHIFT) | X86_TRAP_ERR_IDT);
+                        paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1Present = 1;
+                    }
+                }
+
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u16Sel     = uSysR0Cs;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u4Type     = bSavedType;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1DescType = 0;
+                paIdt[(0x80 + iCtx) << cIdteShift].Gate.u1Present  = 1;
+            }
+        }
+    }
+    BS3_ASSERT(g_usBs3TestStep < 62000U && g_usBs3TestStep > 32000U);
+
+
+    /** @todo
+     *  - Run \#PF and \#GP (and others?) at CPLs other than zero.
+     *  - Quickly generate all faults.
+     *  - All the peculiarities v8086.
+     */
+
+# if TMPL_BITS != 16
+    Bs3MemFree(pbIdtCopyAlloc, 12*_1K);
+# endif
+}
+#endif /* convert me */
+
+
+/**
+ * Executes one round of SIDT and SGDT tests using one assembly worker.
+ *
+ * This is written with driving everything from the 16-bit or 32-bit worker in
+ * mind, i.e. not assuming the test bitcount is the same as the current.
+ */
+static void bs3CpuBasic2_sidt_sgdt_One(BS3CB2SIDTSGDT const BS3_FAR *pWorker, uint8_t bTestMode, uint8_t bRing,
+                                       uint8_t const *pbExpected)
+{
+    BS3TRAPFRAME        TrapCtx;
+    BS3REGCTX           Ctx;
+    BS3REGCTX           CtxUdExpected;
+    BS3REGCTX           TmpCtx;
+    uint8_t const       cbBuf = 8*2;         /* test buffer area  */
+    uint8_t             abBuf[8*2 + 8 + 8];  /* test buffer w/ misalignment test space and some extra guard. */
+    uint8_t BS3_FAR    *pbBuf  = abBuf;
+    uint8_t const       cbIdtr = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 2+8 : 2+4;
+    bool const          f286   = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80286;
+    uint8_t             bFiller;
+    int                 off;
+    int                 off2;
+    unsigned            cb;
+    uint8_t BS3_FAR    *pbTest;
+
+    /* make sure they're allocated  */
+    Bs3MemZero(&Ctx, sizeof(Ctx));
+    Bs3MemZero(&CtxUdExpected, sizeof(CtxUdExpected));
+    Bs3MemZero(&TmpCtx, sizeof(TmpCtx));
+    Bs3MemZero(&TrapCtx, sizeof(TrapCtx));
+    Bs3MemZero(&abBuf, sizeof(abBuf));
+
+    /* Create a context, give this routine some more stack space, point the context
+       at our SIDT [xBX] + UD2 combo, and point DS:xBX at abBuf. */
+    Bs3RegCtxSaveEx(&Ctx, bTestMode, 256 /*cbExtraStack*/);
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
+    Bs3RegCtxSetRipCsFromLnkPtr(&Ctx, pWorker->fpfnWorker);
+    if (BS3_MODE_IS_16BIT_SYS(bTestMode))
+        g_uBs3TrapEipHint = Ctx.rip.u32;
+    if (!BS3_MODE_IS_RM_OR_V86(bTestMode))
+        Bs3RegCtxConvertToRingX(&Ctx, bRing);
+
+    /* For successful SIDT attempts, we'll stop at the UD2. */
+    Bs3MemCpy(&CtxUdExpected, &Ctx, sizeof(Ctx));
+    CtxUdExpected.rip.u += pWorker->cbInstr;
+
+    /*
+     * Check that it works at all and that only bytes we expect gets written to.
+     */
+    /* First with zero buffer. */
+    Bs3MemZero(abBuf, sizeof(abBuf));
+    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), 0))
+        Bs3TestFailedF("ASMMemIsAllU8 or Bs3MemZero is busted: abBuf=%.*Rhxs\n", sizeof(abBuf), pbBuf);
+    if (!ASMMemIsZero(abBuf, sizeof(abBuf)))
+        Bs3TestFailedF("ASMMemIsZero or Bs3MemZero is busted: abBuf=%.*Rhxs\n", sizeof(abBuf), pbBuf);
+    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+    if (f286 && abBuf[cbIdtr - 1] != 0xff)
+        Bs3TestFailedF("286: Top base byte isn't 0xff (#1): %#x\n", abBuf[cbIdtr - 1]);
+    if (!ASMMemIsZero(&abBuf[cbIdtr], cbBuf - cbIdtr))
+        Bs3TestFailedF("Unexpected buffer bytes set (#1): cbIdtr=%u abBuf=%.*Rhxs\n", cbIdtr, cbBuf, pbBuf);
+    if (Bs3MemCmp(abBuf, pbExpected, cbIdtr) != 0)
+        Bs3TestFailedF("Mismatch (%s,#1): expected %.*Rhxs, got %.*Rhxs\n", pWorker->pszDesc, cbIdtr, pbExpected, cbIdtr, abBuf);
+    g_usBs3TestStep++;
+
+    /* Again with a buffer filled with a byte not occuring in the previous result. */
+    bFiller = 0x55;
+    while (Bs3MemChr(abBuf, bFiller, cbBuf) != NULL)
+        bFiller++;
+    Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
+    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
+        Bs3TestFailedF("ASMMemIsAllU8 or Bs3MemSet is busted: bFiller=%#x abBuf=%.*Rhxs\n", bFiller, sizeof(abBuf), pbBuf);
+
+    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+    if (f286 && abBuf[cbIdtr - 1] != 0xff)
+        Bs3TestFailedF("286: Top base byte isn't 0xff (#2): %#x\n", abBuf[cbIdtr - 1]);
+    if (!ASMMemIsAllU8(&abBuf[cbIdtr], cbBuf - cbIdtr, bFiller))
+        Bs3TestFailedF("Unexpected buffer bytes set (#2): cbIdtr=%u bFiller=%#x abBuf=%.*Rhxs\n", cbIdtr, bFiller, cbBuf, pbBuf);
+    if (Bs3MemChr(abBuf, bFiller, cbIdtr) != NULL)
+        Bs3TestFailedF("Not all bytes touched: cbIdtr=%u bFiller=%#x abBuf=%.*Rhxs\n", cbIdtr, bFiller, cbBuf, pbBuf);
+    if (Bs3MemCmp(abBuf, pbExpected, cbIdtr) != 0)
+        Bs3TestFailedF("Mismatch (%s,#2): expected %.*Rhxs, got %.*Rhxs\n", pWorker->pszDesc, cbIdtr, pbExpected, cbIdtr, abBuf);
+    g_usBs3TestStep++;
+
+    /*
+     * Slide the buffer along 8 bytes to cover misalignment.
+     */
+    for (off = 0; off < 8; off++)
+    {
+        pbBuf = &abBuf[off];
+        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &abBuf[off]);
+        CtxUdExpected.rbx.u = Ctx.rbx.u;
+
+        /* First with zero buffer. */
+        Bs3MemZero(abBuf, sizeof(abBuf));
+        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+        if (off > 0 && !ASMMemIsZero(abBuf, off))
+            Bs3TestFailedF("Unexpected buffer bytes set before (#3): cbIdtr=%u off=%u abBuf=%.*Rhxs\n",
+                           cbIdtr, off, off + cbBuf, abBuf);
+        if (!ASMMemIsZero(&abBuf[off + cbIdtr], sizeof(abBuf) - cbIdtr - off))
+            Bs3TestFailedF("Unexpected buffer bytes set after (#3): cbIdtr=%u off=%u abBuf=%.*Rhxs\n",
+                           cbIdtr, off, off + cbBuf, abBuf);
+        if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
+            Bs3TestFailedF("286: Top base byte isn't 0xff (#3): %#x\n", abBuf[off + cbIdtr - 1]);
+        if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
+            Bs3TestFailedF("Mismatch (#3): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
+        g_usBs3TestStep++;
+
+        /* Again with a buffer filled with a byte not occuring in the previous result. */
+        Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
+        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+        if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
+            Bs3TestFailedF("Unexpected buffer bytes set before (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
+        if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - cbIdtr - off, bFiller))
+            Bs3TestFailedF("Unexpected buffer bytes set after (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
+        if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
+            Bs3TestFailedF("Not all bytes touched (#4): cbIdtr=%u off=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                           cbIdtr, off, bFiller, off + cbBuf, abBuf);
+        if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
+            Bs3TestFailedF("286: Top base byte isn't 0xff (#4): %#x\n", abBuf[off + cbIdtr - 1]);
+        if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
+            Bs3TestFailedF("Mismatch (#4): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
+        g_usBs3TestStep++;
+    }
+    pbBuf = abBuf;
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
+    CtxUdExpected.rbx.u = Ctx.rbx.u;
+
+    /*
+     * Play with the selector limit if the target mode supports limit checking
+     * We use BS3_SEL_TEST_PAGE_00 for this
+     */
+    if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
+        && !BS3_MODE_IS_64BIT_CODE(bTestMode))
+    {
+        uint16_t cbLimit;
+        uint32_t uFlatBuf = Bs3SelPtrToFlat(abBuf);
+        Bs3GdteTestPage00 = Bs3Gdte_DATA16;
+        Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
+        Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatBuf;
+        Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatBuf >> 16);
+        Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatBuf >> 24);
+
+        if (pWorker->fSs)
+            CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
+        else
+            CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+
+        /* Expand up (normal). */
+        for (off = 0; off < 8; off++)
+        {
+            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
+            {
+                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (off + cbIdtr <= cbLimit + 1)
+                {
+                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                    if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
+                        Bs3TestFailedF("Not all bytes touched (#5): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                    if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
+                        Bs3TestFailedF("Mismatch (#5): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
+                    if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
+                        Bs3TestFailedF("286: Top base byte isn't 0xff (#5): %#x\n", abBuf[off + cbIdtr - 1]);
+                }
+                else
+                {
+                    if (pWorker->fSs)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                    else
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                    if (off + 2 <= cbLimit + 1)
+                    {
+                        if (Bs3MemChr(&abBuf[off], bFiller, 2) != NULL)
+                            Bs3TestFailedF("Limit bytes not touched (#6): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                           cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                        if (Bs3MemCmp(&abBuf[off], pbExpected, 2) != 0)
+                            Bs3TestFailedF("Mismatch (#6): expected %.2Rhxs, got %.2Rhxs\n", pbExpected, &abBuf[off]);
+                        if (!ASMMemIsAllU8(&abBuf[off + 2], cbIdtr - 2, bFiller))
+                            Bs3TestFailedF("Base bytes touched on #GP (#6): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                           cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                    }
+                    else if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
+                        Bs3TestFailedF("Bytes touched on #GP: cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                }
+
+                if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
+                    Bs3TestFailedF("Leading bytes touched (#7): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - off - cbIdtr, bFiller))
+                    Bs3TestFailedF("Trailing bytes touched (#7): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+
+                g_usBs3TestStep++;
+            }
+        }
+
+        /* Expand down (weird).  Inverted valid area compared to expand up,
+           so a limit of zero give us a valid range for 0001..0ffffh (instead of
+           a segment with one valid byte at 0000h).  Whereas a limit of 0fffeh
+           means one valid byte at 0ffffh, and a limit of 0ffffh means none
+           (because in a normal expand up the 0ffffh means all 64KB are
+           accessible). */
+        Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
+        for (off = 0; off < 8; off++)
+        {
+            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
+            {
+                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                Bs3MemSet(abBuf, bFiller, sizeof(abBuf));
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+
+                if (off > cbLimit)
+                {
+                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                    if (Bs3MemChr(&abBuf[off], bFiller, cbIdtr) != NULL)
+                        Bs3TestFailedF("Not all bytes touched (#8): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                    if (Bs3MemCmp(&abBuf[off], pbExpected, cbIdtr) != 0)
+                        Bs3TestFailedF("Mismatch (#8): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &abBuf[off]);
+                    if (f286 && abBuf[off + cbIdtr - 1] != 0xff)
+                        Bs3TestFailedF("286: Top base byte isn't 0xff (#8): %#x\n", abBuf[off + cbIdtr - 1]);
+                }
+                else
+                {
+                    if (pWorker->fSs)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                    else
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                    if (!ASMMemIsAllU8(abBuf, sizeof(abBuf), bFiller))
+                        Bs3TestFailedF("Bytes touched on #GP: cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                       cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                }
+
+                if (off > 0 && !ASMMemIsAllU8(abBuf, off, bFiller))
+                    Bs3TestFailedF("Leading bytes touched (#9): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+                if (!ASMMemIsAllU8(&abBuf[off + cbIdtr], sizeof(abBuf) - off - cbIdtr, bFiller))
+                    Bs3TestFailedF("Trailing bytes touched (#9): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x abBuf=%.*Rhxs\n",
+                                   cbIdtr, off, cbLimit, bFiller, off + cbBuf, abBuf);
+
+                g_usBs3TestStep++;
+            }
+        }
+
+        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBuf);
+        CtxUdExpected.rbx.u = Ctx.rbx.u;
+        CtxUdExpected.ss = Ctx.ss;
+        CtxUdExpected.ds = Ctx.ds;
+    }
+
+    /*
+     * Play with the paging.
+     */
+    if (   BS3_MODE_IS_PAGED(bTestMode)
+        && (!pWorker->fSs || bRing == 3) /* SS.DPL == CPL, we'll get some tiled ring-3 selector here.  */
+        && (pbTest = (uint8_t BS3_FAR *)Bs3MemGuardedTestPageAlloc(BS3MEMKIND_TILED)) != NULL)
+    {
+        RTCCUINTXREG uFlatTest = Bs3SelPtrToFlat(pbTest);
+
+        /*
+         * Slide the buffer towards the trailing guard page.  We'll observe the
+         * first word being written entirely separately from the 2nd dword/qword.
+         */
+        for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+        {
+            Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller, cbIdtr * 2);
+            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off + cbIdtr <= X86_PAGE_SIZE)
+            {
+                CtxUdExpected.rbx = Ctx.rbx;
+                CtxUdExpected.ss  = Ctx.ss;
+                CtxUdExpected.ds  = Ctx.ds;
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                    Bs3TestFailedF("Mismatch (#9): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+            }
+            else
+            {
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
+                                          uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                if (   off <= X86_PAGE_SIZE - 2
+                    && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
+                    Bs3TestPrintf("Mismatch (#10): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
+                                  pbExpected, &pbTest[off], off);
+                if (   off < X86_PAGE_SIZE - 2
+                    && !ASMMemIsAllU8(&pbTest[off + 2], X86_PAGE_SIZE - off - 2, bFiller))
+                    Bs3TestPrintf("Wrote partial base on #PF (#10): bFiller=%#x, got %.*Rhxs; off=%#x\n",
+                                  bFiller, X86_PAGE_SIZE - off - 2, &pbTest[off + 2], off);
+                if (off == X86_PAGE_SIZE - 1 && pbTest[off] != bFiller)
+                    Bs3TestPrintf("Wrote partial limit on #PF (#10): Expected %02x, got %02x\n", bFiller, pbTest[off]);
+            }
+            g_usBs3TestStep++;
+        }
+
+        /*
+         * Now, do it the other way around. It should look normal now since writing
+         * the limit will #PF first and nothing should be written.
+         */
+        for (off = cbIdtr + 4; off >= -cbIdtr - 4; off--)
+        {
+            Bs3MemSet(pbTest, bFiller, 48);
+            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off >= 0)
+            {
+                CtxUdExpected.rbx = Ctx.rbx;
+                CtxUdExpected.ss  = Ctx.ss;
+                CtxUdExpected.ds  = Ctx.ds;
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                    Bs3TestFailedF("Mismatch (#11): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+            }
+            else
+            {
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0), uFlatTest + off);
+                if (   -off < cbIdtr
+                    && !ASMMemIsAllU8(pbTest, cbIdtr + off, bFiller))
+                    Bs3TestPrintf("Wrote partial content on #PF (#12): bFiller=%#x, found %.*Rhxs; off=%d\n",
+                                  bFiller, cbIdtr + off, pbTest, off);
+            }
+            if (!ASMMemIsAllU8(&pbTest[RT_MAX(cbIdtr + off, 0)], 16, bFiller))
+                Bs3TestPrintf("Wrote beyond expected area (#13): bFiller=%#x, found %.16Rhxs; off=%d\n",
+                              bFiller, &pbTest[RT_MAX(cbIdtr + off, 0)], off);
+            g_usBs3TestStep++;
+        }
+
+        /*
+         * Combine paging and segment limit and check ordering.
+         * This is kind of interesting here since it the instruction seems to
+         * be doing two separate writes.
+         */
+        if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
+            && !BS3_MODE_IS_64BIT_CODE(bTestMode))
+        {
+            uint16_t cbLimit;
+
+            Bs3GdteTestPage00 = Bs3Gdte_DATA16;
+            Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
+            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
+            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
+            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
+
+            if (pWorker->fSs)
+                CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
+            else
+                CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+
+            /* Expand up (normal), approaching tail guard page. */
+            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+            {
+                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
+                {
+                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                    Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller, cbIdtr * 2);
+                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                    if (off + cbIdtr <= cbLimit + 1)
+                    {
+                        /* No #GP, but maybe #PF. */
+                        if (off + cbIdtr <= X86_PAGE_SIZE)
+                        {
+                            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                            if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                                Bs3TestFailedF("Mismatch (#14): expected %.*Rhxs, got %.*Rhxs\n",
+                                               cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+                        }
+                        else
+                        {
+                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
+                                                      uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                            if (   off <= X86_PAGE_SIZE - 2
+                                && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
+                                Bs3TestPrintf("Mismatch (#15): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
+                                              pbExpected, &pbTest[off], off);
+                            cb = X86_PAGE_SIZE - off - 2;
+                            if (   off < X86_PAGE_SIZE - 2
+                                && !ASMMemIsAllU8(&pbTest[off + 2], cb, bFiller))
+                                Bs3TestPrintf("Wrote partial base on #PF (#15): bFiller=%#x, got %.*Rhxs; off=%#x\n",
+                                              bFiller, cb, &pbTest[off + 2], off);
+                            if (off == X86_PAGE_SIZE - 1 && pbTest[off] != bFiller)
+                                Bs3TestPrintf("Wrote partial limit on #PF (#15): Expected %02x, got %02x\n", bFiller, pbTest[off]);
+                        }
+                    }
+                    else if (off + 2 <= cbLimit + 1)
+                    {
+                        /* [ig]tr.limit writing does not cause #GP, but may cause #PG, if not writing the base causes #GP. */
+                        if (off <= X86_PAGE_SIZE - 2)
+                        {
+                            if (pWorker->fSs)
+                                bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                            else
+                                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                            if (Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
+                                Bs3TestPrintf("Mismatch (#16): Expected limit %.2Rhxs, got %.2Rhxs; off=%#x\n",
+                                              pbExpected, &pbTest[off], off);
+                            cb = X86_PAGE_SIZE - off - 2;
+                            if (   off < X86_PAGE_SIZE - 2
+                                && !ASMMemIsAllU8(&pbTest[off + 2], cb, bFiller))
+                                Bs3TestPrintf("Wrote partial base with limit (#16): bFiller=%#x, got %.*Rhxs; off=%#x\n",
+                                              bFiller, cb, &pbTest[off + 2], off);
+                        }
+                        else
+                        {
+                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
+                                                      uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                            if (   off < X86_PAGE_SIZE
+                                && !ASMMemIsAllU8(&pbTest[off], X86_PAGE_SIZE - off, bFiller))
+                                Bs3TestPrintf("Mismatch (#16): Partial limit write on #PF: bFiller=%#x, got %.*Rhxs\n",
+                                              bFiller, X86_PAGE_SIZE - off, &pbTest[off]);
+                        }
+                    }
+                    else
+                    {
+                        /* #GP/#SS on limit. */
+                        if (pWorker->fSs)
+                            bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                        else
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                        if (   off < X86_PAGE_SIZE
+                            && !ASMMemIsAllU8(&pbTest[off], X86_PAGE_SIZE - off, bFiller))
+                            Bs3TestPrintf("Mismatch (#17): Partial write on #GP: bFiller=%#x, got %.*Rhxs\n",
+                                          bFiller, X86_PAGE_SIZE - off, &pbTest[off]);
+                    }
+
+                    cb = RT_MIN(cbIdtr * 2, off - (X86_PAGE_SIZE - cbIdtr*2));
+                    if (!ASMMemIsAllU8(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], cb, bFiller))
+                        Bs3TestFailedF("Leading bytes touched (#18): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
+                                       cbIdtr, off, cbLimit, bFiller, cb, pbTest[X86_PAGE_SIZE - cbIdtr * 2]);
+
+                    g_usBs3TestStep++;
+
+                    /* Set DS to 0 and check that we get #GP(0). */
+                    if (!pWorker->fSs)
+                    {
+                        Ctx.ds = 0;
+                        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                        Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+                        g_usBs3TestStep++;
+                    }
+                }
+            }
+
+            /* Expand down. */
+            pbTest    -= X86_PAGE_SIZE; /* Note! we're backing up a page to simplify things */
+            uFlatTest -= X86_PAGE_SIZE;
+
+            Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
+            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
+            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
+            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
+
+            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+            {
+                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
+                {
+                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                    Bs3MemSet(&pbTest[X86_PAGE_SIZE], bFiller, cbIdtr * 2);
+                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                    if (cbLimit < off && off >= X86_PAGE_SIZE)
+                    {
+                        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                        if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                            Bs3TestFailedF("Mismatch (#19): expected %.*Rhxs, got %.*Rhxs\n",
+                                           cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+                        cb = X86_PAGE_SIZE + cbIdtr*2 - off;
+                        if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], cb, bFiller))
+                            Bs3TestFailedF("Trailing bytes touched (#20): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
+                                           cbIdtr, off, cbLimit, bFiller, cb, pbTest[off + cbIdtr]);
+                    }
+                    else
+                    {
+                        if (cbLimit < off && off < X86_PAGE_SIZE)
+                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, X86_TRAP_PF_RW | (Ctx.bCpl == 3 ? X86_TRAP_PF_US : 0),
+                                                      uFlatTest + off);
+                        else if (pWorker->fSs)
+                            bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                        else
+                            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                        cb = cbIdtr*2;
+                        if (!ASMMemIsAllU8(&pbTest[X86_PAGE_SIZE], cb, bFiller))
+                            Bs3TestFailedF("Trailing bytes touched (#20): cbIdtr=%u off=%u cbLimit=%u bFiller=%#x pbTest=%.*Rhxs\n",
+                                           cbIdtr, off, cbLimit, bFiller, cb, pbTest[X86_PAGE_SIZE]);
+                    }
+                    g_usBs3TestStep++;
+                }
+            }
+
+            pbTest    += X86_PAGE_SIZE;
+            uFlatTest += X86_PAGE_SIZE;
+        }
+
+        Bs3MemGuardedTestPageFree(pbTest);
+    }
+
+    /*
+     * Check non-canonical 64-bit space.
+     */
+    if (   BS3_MODE_IS_64BIT_CODE(bTestMode)
+        && (pbTest = (uint8_t BS3_FAR *)Bs3PagingSetupCanonicalTraps()) != NULL)
+    {
+        /* Make our references relative to the gap. */
+        pbTest += g_cbBs3PagingOneCanonicalTrap;
+
+        /* Hit it from below. */
+        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
+        {
+            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0x0000800000000000) + off;
+            Bs3MemSet(&pbTest[-64], bFiller, 64*2);
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off + cbIdtr <= 0)
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                    Bs3TestFailedF("Mismatch (#21): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+            }
+            else
+            {
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                if (off <= -2 && Bs3MemCmp(&pbTest[off], pbExpected, 2) != 0)
+                    Bs3TestFailedF("Mismatch (#21): expected limit %.2Rhxs, got %.2Rhxs\n", pbExpected, &pbTest[off]);
+                off2 = off <= -2 ? 2 : 0;
+                cb   = cbIdtr - off2;
+                if (!ASMMemIsAllU8(&pbTest[off + off2], cb, bFiller))
+                    Bs3TestFailedF("Mismatch (#21): touched base %.*Rhxs, got %.*Rhxs\n",
+                                   cb, &pbExpected[off], cb, &pbTest[off + off2]);
+            }
+            if (!ASMMemIsAllU8(&pbTest[off - 16], 16, bFiller))
+                Bs3TestFailedF("Leading bytes touched (#21): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off]);
+            if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], 16, bFiller))
+                Bs3TestFailedF("Trailing bytes touched (#21): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off + cbIdtr]);
+        }
+
+        /* Hit it from above. */
+        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
+        {
+            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0xffff800000000000) + off;
+            Bs3MemSet(&pbTest[-64], bFiller, 64*2);
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off >= 0)
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(&pbTest[off], pbExpected, cbIdtr) != 0)
+                    Bs3TestFailedF("Mismatch (#22): expected %.*Rhxs, got %.*Rhxs\n", cbIdtr, pbExpected, cbIdtr, &pbTest[off]);
+            }
+            else
+            {
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                if (!ASMMemIsAllU8(&pbTest[off], cbIdtr, bFiller))
+                    Bs3TestFailedF("Mismatch (#22): touched base %.*Rhxs, got %.*Rhxs\n",
+                                   cbIdtr, &pbExpected[off], cbIdtr, &pbTest[off]);
+            }
+            if (!ASMMemIsAllU8(&pbTest[off - 16], 16, bFiller))
+                Bs3TestFailedF("Leading bytes touched (#22): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off]);
+            if (!ASMMemIsAllU8(&pbTest[off + cbIdtr], 16, bFiller))
+                Bs3TestFailedF("Trailing bytes touched (#22): bFiller=%#x, got %.16Rhxs\n", bFiller, &pbTest[off + cbIdtr]);
+        }
+
+    }
+}
+
+
+static void bs3CpuBasic2_sidt_sgdt_Common(uint8_t bTestMode, BS3CB2SIDTSGDT const BS3_FAR *paWorkers, unsigned cWorkers,
+                                          uint8_t const *pbExpected)
+{
+    unsigned idx;
+    unsigned bRing;
+    unsigned iStep = 0;
+
+    /* Note! We skip the SS checks for ring-0 since we badly mess up SS in the
+             test and don't want to bother with double faults. */
+    for (bRing = 0; bRing <= 3; bRing++)
+    {
+        for (idx = 0; idx < cWorkers; idx++)
+            if (    (paWorkers[idx].bMode & (bTestMode & BS3_MODE_CODE_MASK))
+                && (!paWorkers[idx].fSs || bRing != 0 /** @todo || BS3_MODE_IS_64BIT_SYS(bTestMode)*/ ))
+            {
+                g_usBs3TestStep = iStep;
+                bs3CpuBasic2_sidt_sgdt_One(&paWorkers[idx], bTestMode, bRing, pbExpected);
+                iStep += 1000;
+            }
+        if (BS3_MODE_IS_RM_OR_V86(bTestMode))
+            break;
+    }
+}
+
+
+BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_sidt)(uint8_t bMode)
+{
+    union
+    {
+        RTIDTR  Idtr;
+        uint8_t ab[16];
+    } Expected;
+
+    g_pszTestMode = Bs3GetModeName(bMode);
+    g_bTestMode   = bMode;
+    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
+
+
+    /*
+     * Pass to common worker which is only compiled once per mode.
+     */
+    Bs3MemZero(&Expected, sizeof(Expected));
+    ASMGetIDTR(&Expected.Idtr);
+    bs3CpuBasic2_sidt_sgdt_Common(bMode, g_aSidtWorkers, RT_ELEMENTS(g_aSidtWorkers), Expected.ab);
+
+    /*
+     * Re-initialize the IDT.
+     */
+    Bs3TrapReInit();
+    return 0;
+}
+
+
+BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_sgdt)(uint8_t bMode)
+{
+    uint64_t const uOrgAddr = Bs3Lgdt_Gdt.uAddr;
+    uint64_t       uNew     = 0;
+    union
+    {
+        RTGDTR  Gdtr;
+        uint8_t ab[16];
+    } Expected;
+
+    g_pszTestMode = Bs3GetModeName(bMode);
+    g_bTestMode   = bMode;
+    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
+
+    /*
+     * If paged mode, try push the GDT way up.
+     */
+    Bs3MemZero(&Expected, sizeof(Expected));
+    ASMGetGDTR(&Expected.Gdtr);
+    if (BS3_MODE_IS_PAGED(bMode))
+    {
+/** @todo loading non-canonical base addresses.   */
+        int rc;
+        uNew  = BS3_MODE_IS_64BIT_SYS(bMode) ? UINT64_C(0xffff80fedcb70000) : UINT64_C(0xc2d28000);
+        uNew |= uOrgAddr & X86_PAGE_OFFSET_MASK;
+        rc = Bs3PagingAlias(uNew, uOrgAddr, Bs3Lgdt_Gdt.cb, X86_PTE_P | X86_PTE_RW | X86_PTE_US | X86_PTE_D | X86_PTE_A);
+        if (RT_SUCCESS(rc))
+        {
+            Bs3Lgdt_Gdt.uAddr = uNew;
+            Bs3UtilSetFullGdtr(Bs3Lgdt_Gdt.cb, uNew);
+            ASMGetGDTR(&Expected.Gdtr);
+            if (BS3_MODE_IS_64BIT_SYS(bMode) && ARCH_BITS != 64)
+                *(uint32_t *)&Expected.ab[6] = (uint32_t)(uNew >> 32);
+        }
+    }
+
+    /*
+     * Pass to common worker which is only compiled once per mode.
+     */
+    bs3CpuBasic2_sidt_sgdt_Common(bMode, g_aSgdtWorkers, RT_ELEMENTS(g_aSgdtWorkers), Expected.ab);
+
+    /*
+     * Unalias the GDT.
+     */
+    if (uNew != 0)
+    {
+        Bs3Lgdt_Gdt.uAddr = uOrgAddr;
+        Bs3UtilSetFullGdtr(Bs3Lgdt_Gdt.cb, uOrgAddr);
+        Bs3PagingUnalias(uNew, Bs3Lgdt_Gdt.cb);
+    }
+
+    /*
+     * Re-initialize the IDT.
+     */
+    Bs3TrapReInit();
+    return 0;
+}
+
+
+
+/*
+ * LIDT & LGDT
+ */
+
+/**
+ * Executes one round of LIDT and LGDT tests using one assembly worker.
+ *
+ * This is written with driving everything from the 16-bit or 32-bit worker in
+ * mind, i.e. not assuming the test bitcount is the same as the current.
+ */
+static void bs3CpuBasic2_lidt_lgdt_One(BS3CB2SIDTSGDT const BS3_FAR *pWorker, uint8_t bTestMode, uint8_t bRing,
+                                       uint8_t const *pbRestore, size_t cbRestore, uint8_t const *pbExpected)
+{
+    static const struct
+    {
+        bool        fGP;
+        uint16_t    cbLimit;
+        uint64_t    u64Base;
+    } s_aValues64[] =
+    {
+        { false, 0x0000, UINT64_C(0x0000000000000000) },
+        { false, 0x0001, UINT64_C(0x0000000000000001) },
+        { false, 0x0002, UINT64_C(0x0000000000000010) },
+        { false, 0x0003, UINT64_C(0x0000000000000123) },
+        { false, 0x0004, UINT64_C(0x0000000000001234) },
+        { false, 0x0005, UINT64_C(0x0000000000012345) },
+        { false, 0x0006, UINT64_C(0x0000000000123456) },
+        { false, 0x0007, UINT64_C(0x0000000001234567) },
+        { false, 0x0008, UINT64_C(0x0000000012345678) },
+        { false, 0x0009, UINT64_C(0x0000000123456789) },
+        { false, 0x000a, UINT64_C(0x000000123456789a) },
+        { false, 0x000b, UINT64_C(0x00000123456789ab) },
+        { false, 0x000c, UINT64_C(0x0000123456789abc) },
+        { false, 0x001c, UINT64_C(0x00007ffffeefefef) },
+        { false, 0xffff, UINT64_C(0x00007fffffffffff) },
+        {  true, 0xf3f1, UINT64_C(0x0000800000000000) },
+        {  true, 0x0000, UINT64_C(0x0000800000000000) },
+        {  true, 0x0000, UINT64_C(0x0000800000000333) },
+        {  true, 0x00f0, UINT64_C(0x0001000000000000) },
+        {  true, 0x0ff0, UINT64_C(0x0012000000000000) },
+        {  true, 0x0eff, UINT64_C(0x0123000000000000) },
+        {  true, 0xe0fe, UINT64_C(0x1234000000000000) },
+        {  true, 0x00ad, UINT64_C(0xffff300000000000) },
+        {  true, 0x0000, UINT64_C(0xffff7fffffffffff) },
+        {  true, 0x00f0, UINT64_C(0xffff7fffffffffff) },
+        { false, 0x5678, UINT64_C(0xffff800000000000) },
+        { false, 0x2969, UINT64_C(0xffffffffffeefefe) },
+        { false, 0x1221, UINT64_C(0xffffffffffffffff) },
+        { false, 0x1221, UINT64_C(0xffffffffffffffff) },
+    };
+    static const struct
+    {
+        uint16_t    cbLimit;
+        uint32_t    u32Base;
+    } s_aValues32[] =
+    {
+        { 0xdfdf, UINT32_C(0xefefefef) },
+        { 0x0000, UINT32_C(0x00000000) },
+        { 0x0001, UINT32_C(0x00000001) },
+        { 0x0002, UINT32_C(0x00000012) },
+        { 0x0003, UINT32_C(0x00000123) },
+        { 0x0004, UINT32_C(0x00001234) },
+        { 0x0005, UINT32_C(0x00012345) },
+        { 0x0006, UINT32_C(0x00123456) },
+        { 0x0007, UINT32_C(0x01234567) },
+        { 0x0008, UINT32_C(0x12345678) },
+        { 0x0009, UINT32_C(0x80204060) },
+        { 0x000a, UINT32_C(0xddeeffaa) },
+        { 0x000b, UINT32_C(0xfdecdbca) },
+        { 0x000c, UINT32_C(0x6098456b) },
+        { 0x000d, UINT32_C(0x98506099) },
+        { 0x000e, UINT32_C(0x206950bc) },
+        { 0x000f, UINT32_C(0x9740395d) },
+        { 0x0334, UINT32_C(0x64a9455e) },
+        { 0xb423, UINT32_C(0xd20b6eff) },
+        { 0x4955, UINT32_C(0x85296d46) },
+        { 0xffff, UINT32_C(0x07000039) },
+        { 0xefe1, UINT32_C(0x0007fe00) },
+    };
+
+    BS3TRAPFRAME        TrapCtx;
+    BS3REGCTX           Ctx;
+    BS3REGCTX           CtxUdExpected;
+    BS3REGCTX           TmpCtx;
+    uint8_t             abBufLoad[40];          /* Test buffer w/ misalignment test space and some (cbIdtr) extra guard. */
+    uint8_t             abBufSave[32];          /* For saving the result after loading. */
+    uint8_t             abBufRestore[24];       /* For restoring sane value (same seg as abBufSave!). */
+    uint8_t             abExpectedFilled[32];   /* Same as pbExpected, except it's filled with bFiller2 instead of zeros. */
+    uint8_t BS3_FAR    *pbBufSave;              /* Correctly aligned pointer into abBufSave. */
+    uint8_t BS3_FAR    *pbBufRestore;           /* Correctly aligned pointer into abBufRestore. */
+    uint8_t const       cbIdtr        = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 2+8 : 2+4;
+    uint8_t const       cbBaseLoaded  = BS3_MODE_IS_64BIT_CODE(bTestMode) ? 8
+                                      : BS3_MODE_IS_16BIT_CODE(bTestMode) == !(pWorker->fFlags & BS3CB2SIDTSGDT_F_OPSIZE)
+                                      ? 3 : 4;
+    bool const          f286          = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80286;
+    uint8_t const       bTop16BitBase = f286 ? 0xff : 0x00;
+    uint8_t             bFiller1;               /* For filling abBufLoad.  */
+    uint8_t             bFiller2;               /* For filling abBufSave and expectations. */
+    int                 off;
+    uint8_t BS3_FAR    *pbTest;
+    unsigned            i;
+
+    /* make sure they're allocated  */
+    Bs3MemZero(&Ctx, sizeof(Ctx));
+    Bs3MemZero(&CtxUdExpected, sizeof(CtxUdExpected));
+    Bs3MemZero(&TmpCtx, sizeof(TmpCtx));
+    Bs3MemZero(&TrapCtx, sizeof(TrapCtx));
+    Bs3MemZero(abBufSave, sizeof(abBufSave));
+    Bs3MemZero(abBufLoad, sizeof(abBufLoad));
+    Bs3MemZero(abBufRestore, sizeof(abBufRestore));
+
+    /*
+     * Create a context, giving this routine some more stack space.
+     *  - Point the context at our LIDT [xBX] + SIDT [xDI] + LIDT [xSI] + UD2 combo.
+     *  - Point DS/SS:xBX at abBufLoad.
+     *  - Point ES:xDI at abBufSave.
+     *  - Point ES:xSI at abBufRestore.
+     */
+    Bs3RegCtxSaveEx(&Ctx, bTestMode, 256 /*cbExtraStack*/);
+    Bs3RegCtxSetRipCsFromLnkPtr(&Ctx, pWorker->fpfnWorker);
+    if (BS3_MODE_IS_16BIT_SYS(bTestMode))
+        g_uBs3TrapEipHint = Ctx.rip.u32;
+    Ctx.rflags.u16 &= ~X86_EFL_IF;
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
+
+    pbBufSave = abBufSave;
+    if ((BS3_FP_OFF(pbBufSave) + 2) & 7)
+        pbBufSave += 8 - ((BS3_FP_OFF(pbBufSave) + 2) & 7);
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rdi, &Ctx.es, pbBufSave);
+
+    pbBufRestore = abBufRestore;
+    if ((BS3_FP_OFF(pbBufRestore) + 2) & 7)
+        pbBufRestore += 8 - ((BS3_FP_OFF(pbBufRestore) + 2) & 7);
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rsi, &Ctx.es, pbBufRestore);
+    Bs3MemCpy(pbBufRestore, pbRestore, cbRestore);
+
+    if (!BS3_MODE_IS_RM_OR_V86(bTestMode))
+        Bs3RegCtxConvertToRingX(&Ctx, bRing);
+
+    /* For successful SIDT attempts, we'll stop at the UD2. */
+    Bs3MemCpy(&CtxUdExpected, &Ctx, sizeof(Ctx));
+    CtxUdExpected.rip.u += pWorker->cbInstr;
+
+    /*
+     * Check that it works at all.
+     */
+    Bs3MemZero(abBufLoad, sizeof(abBufLoad));
+    Bs3MemCpy(abBufLoad, pbBufRestore, cbIdtr);
+    Bs3MemZero(abBufSave, sizeof(abBufSave));
+    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+    if (bRing != 0)
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+    else
+    {
+        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+        if (Bs3MemCmp(pbBufSave, pbExpected, cbIdtr * 2) != 0)
+            Bs3TestFailedF("Mismatch (%s, #1): expected %.*Rhxs, got %.*Rhxs\n",
+                           pWorker->pszDesc, cbIdtr*2, pbExpected, cbIdtr*2, pbBufSave);
+    }
+    g_usBs3TestStep++;
+
+    /* Determine two filler bytes that doesn't appear in the previous result or our expectations. */
+    bFiller1 = ~0x55;
+    while (   Bs3MemChr(pbBufSave, bFiller1, cbIdtr) != NULL
+           || Bs3MemChr(pbRestore, bFiller1, cbRestore) != NULL
+           || bFiller1 == 0xff)
+        bFiller1++;
+    bFiller2 = 0x33;
+    while (   Bs3MemChr(pbBufSave, bFiller2, cbIdtr) != NULL
+           || Bs3MemChr(pbRestore, bFiller2, cbRestore) != NULL
+           || bFiller2 == 0xff
+           || bFiller2 == bFiller1)
+        bFiller2++;
+    Bs3MemSet(abExpectedFilled, bFiller2, sizeof(abExpectedFilled));
+    Bs3MemCpy(abExpectedFilled, pbExpected, cbIdtr);
+
+    /* Again with a buffer filled with a byte not occuring in the previous result. */
+    Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+    Bs3MemCpy(abBufLoad, pbBufRestore, cbIdtr);
+    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+    if (bRing != 0)
+        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+    else
+    {
+        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+        if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+            Bs3TestFailedF("Mismatch (%s, #2): expected %.*Rhxs, got %.*Rhxs\n",
+                           pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+    }
+    g_usBs3TestStep++;
+
+    /*
+     * Try loading a bunch of different limit+base value to check what happens,
+     * especially what happens wrt the top part of the base in 16-bit mode.
+     */
+    if (BS3_MODE_IS_64BIT_CODE(bTestMode))
+    {
+        for (i = 0; i < RT_ELEMENTS(s_aValues64); i++)
+        {
+            Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+            Bs3MemCpy(&abBufLoad[0], &s_aValues64[i].cbLimit, 2);
+            Bs3MemCpy(&abBufLoad[2], &s_aValues64[i].u64Base, 8);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (bRing != 0 || s_aValues64[i].fGP)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (   Bs3MemCmp(&pbBufSave[0], &s_aValues64[i].cbLimit, 2) != 0
+                    || Bs3MemCmp(&pbBufSave[2], &s_aValues64[i].u64Base, 8) != 0
+                    || !ASMMemIsAllU8(&pbBufSave[10], cbIdtr, bFiller2))
+                    Bs3TestFailedF("Mismatch (%s, #2): expected %04RX16:%016RX64, fillers %#x %#x, got %.*Rhxs\n",
+                                   pWorker->pszDesc, s_aValues64[i].cbLimit, s_aValues64[i].u64Base,
+                                   bFiller1, bFiller2, cbIdtr*2, pbBufSave);
+            }
+            g_usBs3TestStep++;
+        }
+    }
+    else
+    {
+        for (i = 0; i < RT_ELEMENTS(s_aValues32); i++)
+        {
+            Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+            Bs3MemCpy(&abBufLoad[0], &s_aValues32[i].cbLimit, 2);
+            Bs3MemCpy(&abBufLoad[2], &s_aValues32[i].u32Base, cbBaseLoaded);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (bRing != 0)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (   Bs3MemCmp(&pbBufSave[0], &s_aValues32[i].cbLimit, 2) != 0
+                    || Bs3MemCmp(&pbBufSave[2], &s_aValues32[i].u32Base, cbBaseLoaded) != 0
+                    || (   cbBaseLoaded != 4
+                        && pbBufSave[2+3] != bTop16BitBase)
+                    || !ASMMemIsAllU8(&pbBufSave[8], cbIdtr, bFiller2))
+                    Bs3TestFailedF("Mismatch (%s,#3): loaded %04RX16:%08RX32, fillers %#x %#x%s, got %.*Rhxs\n",
+                                   pWorker->pszDesc, s_aValues32[i].cbLimit, s_aValues32[i].u32Base, bFiller1, bFiller2,
+                                   f286 ? ", 286" : "", cbIdtr*2, pbBufSave);
+            }
+            g_usBs3TestStep++;
+        }
+    }
+
+    /*
+     * Slide the buffer along 8 bytes to cover misalignment.
+     */
+    for (off = 0; off < 8; off++)
+    {
+        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &abBufLoad[off]);
+        CtxUdExpected.rbx.u = Ctx.rbx.u;
+
+        Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+        Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
+        Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+        if (bRing != 0)
+            bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+        else
+        {
+            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+            if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                Bs3TestFailedF("Mismatch (%s, #4): expected %.*Rhxs, got %.*Rhxs\n",
+                               pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+        }
+        g_usBs3TestStep++;
+    }
+    Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
+    CtxUdExpected.rbx.u = Ctx.rbx.u;
+
+    /*
+     * Play with the selector limit if the target mode supports limit checking
+     * We use BS3_SEL_TEST_PAGE_00 for this
+     */
+    if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
+        && !BS3_MODE_IS_64BIT_CODE(bTestMode))
+    {
+        uint16_t cbLimit;
+        uint32_t uFlatBuf = Bs3SelPtrToFlat(abBufLoad);
+        Bs3GdteTestPage00 = Bs3Gdte_DATA16;
+        Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
+        Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatBuf;
+        Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatBuf >> 16);
+        Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatBuf >> 24);
+
+        if (pWorker->fSs)
+            CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
+        else
+            CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+
+        /* Expand up (normal). */
+        for (off = 0; off < 8; off++)
+        {
+            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
+            {
+                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+
+                Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+                Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
+                Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (bRing != 0)
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                else if (off + cbIdtr <= cbLimit + 1)
+                {
+                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                    if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                        Bs3TestFailedF("Mismatch (%s, #5): expected %.*Rhxs, got %.*Rhxs\n",
+                                       pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+                }
+                else if (pWorker->fSs)
+                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                else
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                g_usBs3TestStep++;
+
+                /* Again with zero limit and messed up base (should trigger tripple fault if partially loaded). */
+                abBufLoad[off] = abBufLoad[off + 1] = 0;
+                abBufLoad[off + 2] |= 1;
+                abBufLoad[off + cbIdtr - 2] ^= 0x5a;
+                abBufLoad[off + cbIdtr - 1] ^= 0xa5;
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (bRing != 0)
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                else if (off + cbIdtr <= cbLimit + 1)
+                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                else if (pWorker->fSs)
+                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                else
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            }
+        }
+
+        /* Expand down (weird).  Inverted valid area compared to expand up,
+           so a limit of zero give us a valid range for 0001..0ffffh (instead of
+           a segment with one valid byte at 0000h).  Whereas a limit of 0fffeh
+           means one valid byte at 0ffffh, and a limit of 0ffffh means none
+           (because in a normal expand up the 0ffffh means all 64KB are
+           accessible). */
+        Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
+        for (off = 0; off < 8; off++)
+        {
+            CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+            for (cbLimit = 0; cbLimit < cbIdtr*2; cbLimit++)
+            {
+                Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+
+                Bs3MemSet(abBufLoad, bFiller1, sizeof(abBufLoad));
+                Bs3MemCpy(&abBufLoad[off], pbBufRestore, cbIdtr);
+                Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (bRing != 0)
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                else if (off > cbLimit)
+                {
+                    bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                    if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                        Bs3TestFailedF("Mismatch (%s, #6): expected %.*Rhxs, got %.*Rhxs\n",
+                                       pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+                }
+                else if (pWorker->fSs)
+                    bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                else
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+               g_usBs3TestStep++;
+
+               /* Again with zero limit and messed up base (should trigger triple fault if partially loaded). */
+               abBufLoad[off] = abBufLoad[off + 1] = 0;
+               abBufLoad[off + 2] |= 3;
+               abBufLoad[off + cbIdtr - 2] ^= 0x55;
+               abBufLoad[off + cbIdtr - 1] ^= 0xaa;
+               Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+               if (bRing != 0)
+                   bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+               else if (off > cbLimit)
+                   bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+               else if (pWorker->fSs)
+                   bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+               else
+                   bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            }
+        }
+
+        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, abBufLoad);
+        CtxUdExpected.rbx.u = Ctx.rbx.u;
+        CtxUdExpected.ss = Ctx.ss;
+        CtxUdExpected.ds = Ctx.ds;
+    }
+
+    /*
+     * Play with the paging.
+     */
+    if (   BS3_MODE_IS_PAGED(bTestMode)
+        && (!pWorker->fSs || bRing == 3) /* SS.DPL == CPL, we'll get some tiled ring-3 selector here.  */
+        && (pbTest = (uint8_t BS3_FAR *)Bs3MemGuardedTestPageAlloc(BS3MEMKIND_TILED)) != NULL)
+    {
+        RTCCUINTXREG uFlatTest = Bs3SelPtrToFlat(pbTest);
+
+        /*
+         * Slide the load buffer towards the trailing guard page.
+         */
+        Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[X86_PAGE_SIZE]);
+        CtxUdExpected.ss = Ctx.ss;
+        CtxUdExpected.ds = Ctx.ds;
+        for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+        {
+            Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller1, cbIdtr*2);
+            if (off < X86_PAGE_SIZE)
+                Bs3MemCpy(&pbTest[off], pbBufRestore, RT_MIN(X86_PAGE_SIZE - off, cbIdtr));
+            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (bRing != 0)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else if (off + cbIdtr <= X86_PAGE_SIZE)
+            {
+                CtxUdExpected.rbx = Ctx.rbx;
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr*2) != 0)
+                    Bs3TestFailedF("Mismatch (%s, #7): expected %.*Rhxs, got %.*Rhxs\n",
+                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+            }
+            else
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+            g_usBs3TestStep++;
+
+            /* Again with zero limit and maybe messed up base as well (triple fault if buggy).
+               The 386DX-40 here triple faults (or something) with off == 0xffe, nothing else. */
+            if (   off < X86_PAGE_SIZE && off + cbIdtr > X86_PAGE_SIZE
+                && (   off != X86_PAGE_SIZE - 2
+                    || (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) != BS3CPU_80386)
+                )
+            {
+                pbTest[off] = 0;
+                if (off + 1 < X86_PAGE_SIZE)
+                    pbTest[off + 1] = 0;
+                if (off + 2 < X86_PAGE_SIZE)
+                    pbTest[off + 2] |= 7;
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (bRing != 0)
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                else
+                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                g_usBs3TestStep++;
+            }
+        }
+
+        /*
+         * Now, do it the other way around. It should look normal now since writing
+         * the limit will #PF first and nothing should be written.
+         */
+        for (off = cbIdtr + 4; off >= -cbIdtr - 4; off--)
+        {
+            Bs3MemSet(pbTest, bFiller1, 48);
+            if (off >= 0)
+                Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
+            else if (off + cbIdtr > 0)
+                Bs3MemCpy(pbTest, &pbBufRestore[-off], cbIdtr + off);
+            Bs3RegCtxSetGrpSegFromCurPtr(&Ctx, &Ctx.rbx, pWorker->fSs ? &Ctx.ss : &Ctx.ds, &pbTest[off]);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (bRing != 0)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else if (off >= 0)
+            {
+                CtxUdExpected.rbx = Ctx.rbx;
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr*2) != 0)
+                    Bs3TestFailedF("Mismatch (%s, #8): expected %.*Rhxs, got %.*Rhxs\n",
+                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+            }
+            else
+                bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
+            g_usBs3TestStep++;
+
+            /* Again with messed up base as well (triple fault if buggy). */
+            if (off < 0 && off > -cbIdtr)
+            {
+                if (off + 2 >= 0)
+                    pbTest[off + 2] |= 15;
+                pbTest[off + cbIdtr - 1] ^= 0xaa;
+                Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                if (bRing != 0)
+                    bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                else
+                    bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
+                g_usBs3TestStep++;
+            }
+        }
+
+        /*
+         * Combine paging and segment limit and check ordering.
+         * This is kind of interesting here since it the instruction seems to
+         * actually be doing two separate read, just like it's S[IG]DT counterpart.
+         *
+         * Note! My 486DX4 does a DWORD limit read when the operand size is 32-bit,
+         *       that's what f486Weirdness deals with.
+         */
+        if (   !BS3_MODE_IS_RM_OR_V86(bTestMode)
+            && !BS3_MODE_IS_64BIT_CODE(bTestMode))
+        {
+            bool const f486Weirdness = (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) == BS3CPU_80486
+                                    && BS3_MODE_IS_32BIT_CODE(bTestMode) == !(pWorker->fFlags & BS3CB2SIDTSGDT_F_OPSIZE);
+            uint16_t   cbLimit;
+
+            Bs3GdteTestPage00 = Bs3Gdte_DATA16;
+            Bs3GdteTestPage00.Gen.u2Dpl       = bRing;
+            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
+            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
+            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
+
+            if (pWorker->fSs)
+                CtxUdExpected.ss = Ctx.ss = BS3_SEL_TEST_PAGE_00 | bRing;
+            else
+                CtxUdExpected.ds = Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+
+            /* Expand up (normal), approaching tail guard page. */
+            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+            {
+                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
+                {
+                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                    Bs3MemSet(&pbTest[X86_PAGE_SIZE - cbIdtr * 2], bFiller1, cbIdtr * 2);
+                    if (off < X86_PAGE_SIZE)
+                        Bs3MemCpy(&pbTest[off], pbBufRestore, RT_MIN(cbIdtr, X86_PAGE_SIZE - off));
+                    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                    if (bRing != 0)
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                    else if (off + cbIdtr <= cbLimit + 1)
+                    {
+                        /* No #GP, but maybe #PF. */
+                        if (off + cbIdtr <= X86_PAGE_SIZE)
+                        {
+                            bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                            if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                                Bs3TestFailedF("Mismatch (%s, #9): expected %.*Rhxs, got %.*Rhxs\n",
+                                               pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+                        }
+                        else
+                            bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                    }
+                    /* No #GP/#SS on limit, but instead #PF? */
+                    else if (  !f486Weirdness
+                             ? off     < cbLimit && off >= 0xfff
+                             : off + 2 < cbLimit && off >= 0xffd)
+                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + RT_MAX(off, X86_PAGE_SIZE));
+                    /* #GP/#SS on limit or base. */
+                    else if (pWorker->fSs)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                    else
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+
+                    g_usBs3TestStep++;
+
+                    /* Set DS to 0 and check that we get #GP(0). */
+                    if (!pWorker->fSs)
+                    {
+                        Ctx.ds = 0;
+                        Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                        Ctx.ds = BS3_SEL_TEST_PAGE_00 | bRing;
+                        g_usBs3TestStep++;
+                    }
+                }
+            }
+
+            /* Expand down. */
+            pbTest    -= X86_PAGE_SIZE; /* Note! we're backing up a page to simplify things */
+            uFlatTest -= X86_PAGE_SIZE;
+
+            Bs3GdteTestPage00.Gen.u4Type = X86_SEL_TYPE_RW_DOWN_ACC;
+            Bs3GdteTestPage00.Gen.u16BaseLow  = (uint16_t)uFlatTest;
+            Bs3GdteTestPage00.Gen.u8BaseHigh1 = (uint8_t)(uFlatTest >> 16);
+            Bs3GdteTestPage00.Gen.u8BaseHigh2 = (uint8_t)(uFlatTest >> 24);
+
+            for (off = X86_PAGE_SIZE - cbIdtr - 4; off < X86_PAGE_SIZE + 4; off++)
+            {
+                CtxUdExpected.rbx.u = Ctx.rbx.u = off;
+                for (cbLimit = X86_PAGE_SIZE - cbIdtr*2; cbLimit < X86_PAGE_SIZE + cbIdtr*2; cbLimit++)
+                {
+                    Bs3GdteTestPage00.Gen.u16LimitLow = cbLimit;
+                    Bs3MemSet(&pbTest[X86_PAGE_SIZE], bFiller1, cbIdtr * 2);
+                    if (off >= X86_PAGE_SIZE)
+                        Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
+                    else if (off > X86_PAGE_SIZE - cbIdtr)
+                        Bs3MemCpy(&pbTest[X86_PAGE_SIZE], &pbBufRestore[X86_PAGE_SIZE - off], cbIdtr - (X86_PAGE_SIZE - off));
+                    Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+                    Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+                    if (bRing != 0)
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                    else if (cbLimit < off && off >= X86_PAGE_SIZE)
+                    {
+                        bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                        if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                            Bs3TestFailedF("Mismatch (%s, #10): expected %.*Rhxs, got %.*Rhxs\n",
+                                           pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+                    }
+                    else if (cbLimit < off && off < X86_PAGE_SIZE)
+                        bs3CpuBasic2_ComparePfCtx(&TrapCtx, &Ctx, 0, uFlatTest + off);
+                    else if (pWorker->fSs)
+                        bs3CpuBasic2_CompareSsCtx(&TrapCtx, &Ctx, 0, false /*f486ResumeFlagHint*/);
+                    else
+                        bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+                    g_usBs3TestStep++;
+                }
+            }
+
+            pbTest    += X86_PAGE_SIZE;
+            uFlatTest += X86_PAGE_SIZE;
+        }
+
+        Bs3MemGuardedTestPageFree(pbTest);
+    }
+
+    /*
+     * Check non-canonical 64-bit space.
+     */
+    if (   BS3_MODE_IS_64BIT_CODE(bTestMode)
+        && (pbTest = (uint8_t BS3_FAR *)Bs3PagingSetupCanonicalTraps()) != NULL)
+    {
+        /* Make our references relative to the gap. */
+        pbTest += g_cbBs3PagingOneCanonicalTrap;
+
+        /* Hit it from below. */
+        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
+        {
+            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0x0000800000000000) + off;
+            Bs3MemSet(&pbTest[-64], bFiller1, 64*2);
+            Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off + cbIdtr > 0 || bRing != 0)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                    Bs3TestFailedF("Mismatch (%s, #11): expected %.*Rhxs, got %.*Rhxs\n",
+                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+            }
+        }
+
+        /* Hit it from above. */
+        for (off = -cbIdtr - 8; off < cbIdtr + 8; off++)
+        {
+            Ctx.rbx.u = CtxUdExpected.rbx.u = UINT64_C(0xffff800000000000) + off;
+            Bs3MemSet(&pbTest[-64], bFiller1, 64*2);
+            Bs3MemCpy(&pbTest[off], pbBufRestore, cbIdtr);
+            Bs3MemSet(abBufSave, bFiller2, sizeof(abBufSave));
+            Bs3TrapSetJmpAndRestore(&Ctx, &TrapCtx);
+            if (off < 0 || bRing != 0)
+                bs3CpuBasic2_CompareGpCtx(&TrapCtx, &Ctx, 0);
+            else
+            {
+                bs3CpuBasic2_CompareUdCtx(&TrapCtx, &CtxUdExpected);
+                if (Bs3MemCmp(pbBufSave, abExpectedFilled, cbIdtr * 2) != 0)
+                    Bs3TestFailedF("Mismatch (%s, #19): expected %.*Rhxs, got %.*Rhxs\n",
+                                   pWorker->pszDesc, cbIdtr*2, abExpectedFilled, cbIdtr*2, pbBufSave);
+            }
+        }
+
+    }
+}
+
+
+static void bs3CpuBasic2_lidt_lgdt_Common(uint8_t bTestMode, BS3CB2SIDTSGDT const BS3_FAR *paWorkers, unsigned cWorkers,
+                                          void const *pvRestore, size_t cbRestore, uint8_t const *pbExpected)
+{
+    unsigned idx;
+    unsigned bRing;
+    unsigned iStep = 0;
+
+    /* Note! We skip the SS checks for ring-0 since we badly mess up SS in the
+             test and don't want to bother with double faults. */
+    for (bRing = BS3_MODE_IS_V86(bTestMode) ? 3 : 0; bRing <= 3; bRing++)
+    {
+        for (idx = 0; idx < cWorkers; idx++)
+            if (    (paWorkers[idx].bMode & (bTestMode & BS3_MODE_CODE_MASK))
+                && (!paWorkers[idx].fSs || bRing != 0 /** @todo || BS3_MODE_IS_64BIT_SYS(bTestMode)*/ )
+                && (   !(paWorkers[idx].fFlags & BS3CB2SIDTSGDT_F_386PLUS)
+                    || (   bTestMode > BS3_MODE_PE16
+                        || (   bTestMode == BS3_MODE_PE16
+                            && (g_uBs3CpuDetected & BS3CPU_TYPE_MASK) >= BS3CPU_80386)) ) )
+            {
+                //Bs3TestPrintf("idx=%-2d fpfnWorker=%p fSs=%d cbInstr=%d\n",
+                //              idx, paWorkers[idx].fpfnWorker, paWorkers[idx].fSs, paWorkers[idx].cbInstr);
+                g_usBs3TestStep = iStep;
+                bs3CpuBasic2_lidt_lgdt_One(&paWorkers[idx], bTestMode, bRing, pvRestore, cbRestore, pbExpected);
+                iStep += 1000;
+            }
+        if (BS3_MODE_IS_RM_SYS(bTestMode))
+            break;
+    }
+}
+
+
+BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_lidt)(uint8_t bMode)
+{
+    union
+    {
+        RTIDTR  Idtr;
+        uint8_t ab[32]; /* At least cbIdtr*2! */
+    } Expected;
+
+    g_pszTestMode = Bs3GetModeName(bMode);
+    g_bTestMode   = bMode;
+    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
+
+    /*
+     * Pass to common worker which is only compiled once per mode.
+     */
+    Bs3MemZero(&Expected, sizeof(Expected));
+    ASMGetIDTR(&Expected.Idtr);
+
+    if (BS3_MODE_IS_RM_SYS(bMode))
+        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
+                                      &Bs3Lidt_Ivt, sizeof(Bs3Lidt_Ivt), Expected.ab);
+    else if (BS3_MODE_IS_16BIT_SYS(bMode))
+        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
+                                      &Bs3Lidt_Idt16, sizeof(Bs3Lidt_Idt16), Expected.ab);
+    else if (BS3_MODE_IS_32BIT_SYS(bMode))
+        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
+                                      &Bs3Lidt_Idt32, sizeof(Bs3Lidt_Idt32), Expected.ab);
+    else
+        bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLidtWorkers, RT_ELEMENTS(g_aLidtWorkers),
+                                      &Bs3Lidt_Idt64, sizeof(Bs3Lidt_Idt64), Expected.ab);
+
+    /*
+     * Re-initialize the IDT.
+     */
+    Bs3TrapReInit();
+    return 0;
+}
+
+
+BS3_DECL_FAR(uint8_t) BS3_CMN_FAR_NM(bs3CpuBasic2_lgdt)(uint8_t bMode)
+{
+    union
+    {
+        RTGDTR  Gdtr;
+        uint8_t ab[32]; /* At least cbIdtr*2! */
+    } Expected;
+
+    g_pszTestMode = Bs3GetModeName(bMode);
+    g_bTestMode   = bMode;
+    g_f16BitSys   = BS3_MODE_IS_16BIT_SYS(bMode);
+
+    /*
+     * Pass to common worker which is only compiled once per mode.
+     */
+    if (BS3_MODE_IS_RM_SYS(bMode))
+        ASMSetGDTR((PRTGDTR)&Bs3LgdtDef_Gdt);
+    Bs3MemZero(&Expected, sizeof(Expected));
+    ASMGetGDTR(&Expected.Gdtr);
+
+    bs3CpuBasic2_lidt_lgdt_Common(bMode, g_aLgdtWorkers, RT_ELEMENTS(g_aLgdtWorkers),
+                                  &Bs3LgdtDef_Gdt, sizeof(Bs3LgdtDef_Gdt), Expected.ab);
+
+    /*
+     * Re-initialize the IDT.
+     */
+    Bs3TrapReInit();
+    return 0;
+}
+
Index: /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2.c
===================================================================
--- /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2.c	(revision 60749)
+++ /trunk/src/VBox/ValidationKit/bootsectors/bs3-cpu-basic-2.c	(revision 60750)
@@ -38,9 +38,4 @@
 BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_TssGateEsp);
 BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_RaiseXcpt1);
-BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_iret);
-BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_sidt);
-BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_sgdt);
-BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_lidt);
-BS3TESTMODE_PROTOTYPES_MODE(bs3CpuBasic2_lgdt);
 
 FNBS3TESTDOMODE             bs3CpuBasic2_sidt_f16;
@@ -54,22 +49,16 @@
 *   Global Variables                                                                                                             *
 *********************************************************************************************************************************/
-#if 0
 static const BS3TESTMODEENTRY g_aModeTest[] =
 {
-#if 0
-    BS3TESTMODEENTRY_MODE("tss / gate / esp", bs3CpuBasic2_TssGateEsp),
+    //BS3TESTMODEENTRY_MODE("tss / gate / esp", bs3CpuBasic2_TssGateEsp),
     BS3TESTMODEENTRY_MODE("raise xcpt #1", bs3CpuBasic2_RaiseXcpt1),
-//    BS3TESTMODEENTRY_MODE("sidt", bs3CpuBasic2_sidt),
-//    BS3TESTMODEENTRY_MODE("sgdt", bs3CpuBasic2_sgdt),
-//    BS3TESTMODEENTRY_MODE("lidt", bs3CpuBasic2_lidt),
-//    BS3TESTMODEENTRY_MODE("lgdt", bs3CpuBasic2_lgdt),
-#endif
-//    BS3TESTMODEENTRY_MODE("iret", bs3CpuBasic2_iret),
 };
-#endif
 
 static const BS3TESTMODEBYONEENTRY g_aModeByOneTests[] =
 {
     //{ "iret", bs3CpuBasic2_iret_f16, 0 },
+    { "sidt", bs3CpuBasic2_sidt_f16, 0 },
+    { "sgdt", bs3CpuBasic2_sgdt_f16, 0 },
+    { "lidt", bs3CpuBasic2_lidt_f16, 0 },
     { "lgdt", bs3CpuBasic2_lgdt_f16, 0 },
 };
@@ -82,5 +71,5 @@
     Bs3TestPrintf("g_uBs3CpuDetected=%#x\n", g_uBs3CpuDetected);
 
-    //Bs3TestDoModes_rm(g_aModeTest, RT_ELEMENTS(g_aModeTest));
+    Bs3TestDoModes_rm(g_aModeTest, RT_ELEMENTS(g_aModeTest));
     Bs3TestDoModesByOne_rm(g_aModeByOneTests, RT_ELEMENTS(g_aModeByOneTests), 0);
 
Index: /trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TestDoModesByOneHlp.asm
===================================================================
--- /trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TestDoModesByOneHlp.asm	(revision 60749)
+++ /trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TestDoModesByOneHlp.asm	(revision 60750)
@@ -141,5 +141,4 @@
 
 .return:
-hlt
         ; Switch back to 64-bit mode.
         extern  _Bs3SwitchTo64Bit_c16
