Index: /trunk/src/VBox/VMM/VMMAll/IEMAllAImpl.asm
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/IEMAllAImpl.asm	(revision 65193)
+++ /trunk/src/VBox/VMM/VMMAll/IEMAllAImpl.asm	(revision 65194)
@@ -2483,4 +2483,5 @@
 
 IEMIMPL_FPU_R80_BY_R80_ST1_ST0_POP fpatan
+IEMIMPL_FPU_R80_BY_R80_ST1_ST0_POP fyl2x
 IEMIMPL_FPU_R80_BY_R80_ST1_ST0_POP fyl2xp1
 
@@ -2589,5 +2590,4 @@
 IEMIMPL_FPU_R80 fabs
 IEMIMPL_FPU_R80 f2xm1
-IEMIMPL_FPU_R80 fyl2x
 IEMIMPL_FPU_R80 fsqrt
 IEMIMPL_FPU_R80 frndint
Index: /trunk/src/VBox/VMM/VMMAll/IEMAllInstructions.cpp.h
===================================================================
--- /trunk/src/VBox/VMM/VMMAll/IEMAllInstructions.cpp.h	(revision 65193)
+++ /trunk/src/VBox/VMM/VMMAll/IEMAllInstructions.cpp.h	(revision 65194)
@@ -14286,9 +14286,42 @@
 
 
+/**
+ * Common worker for FPU instructions working on STn and ST0, storing the result
+ * in STn, and popping the stack unless IE, DE or ZE was raised.
+ *
+ * @param   pfnAImpl    Pointer to the instruction implementation (assembly).
+ */
+FNIEMOP_DEF_2(iemOpHlpFpu_stN_st0_pop, uint8_t, bRm, PFNIEMAIMPLFPUR80, pfnAImpl)
+{
+    IEMOP_HLP_DONE_DECODING_NO_LOCK_PREFIX();
+
+    IEM_MC_BEGIN(3, 1);
+    IEM_MC_LOCAL(IEMFPURESULT,          FpuRes);
+    IEM_MC_ARG_LOCAL_REF(PIEMFPURESULT, pFpuRes,        FpuRes,     0);
+    IEM_MC_ARG(PCRTFLOAT80U,            pr80Value1,                 1);
+    IEM_MC_ARG(PCRTFLOAT80U,            pr80Value2,                 2);
+
+    IEM_MC_MAYBE_RAISE_DEVICE_NOT_AVAILABLE();
+    IEM_MC_MAYBE_RAISE_FPU_XCPT();
+
+    IEM_MC_PREPARE_FPU_USAGE();
+    IEM_MC_IF_TWO_FPUREGS_NOT_EMPTY_REF_R80(pr80Value1, bRm & X86_MODRM_RM_MASK, pr80Value2, 0)
+        IEM_MC_CALL_FPU_AIMPL_3(pfnAImpl, pFpuRes, pr80Value1, pr80Value2);
+        IEM_MC_STORE_FPU_RESULT_THEN_POP(FpuRes, bRm & X86_MODRM_RM_MASK);
+    IEM_MC_ELSE()
+        IEM_MC_FPU_STACK_UNDERFLOW_THEN_POP(bRm & X86_MODRM_RM_MASK);
+    IEM_MC_ENDIF();
+    IEM_MC_ADVANCE_RIP();
+
+    IEM_MC_END();
+    return VINF_SUCCESS;
+}
+
+
 /** Opcode 0xd9 0xf1. */
-FNIEMOP_DEF(iemOp_fylx2)
-{
-    IEMOP_MNEMONIC(fylx2_st0, "fylx2 st0");
-    return FNIEMOP_CALL_1(iemOpHlpFpu_st0, iemAImpl_fyl2x_r80);
+FNIEMOP_DEF(iemOp_fyl2x)
+{
+    IEMOP_MNEMONIC(fyl2x_st0, "fyl2x st1,st0");
+    return FNIEMOP_CALL_2(iemOpHlpFpu_stN_st0_pop, 1, iemAImpl_fyl2x_r80_by_r80);
 }
 
@@ -14330,37 +14363,4 @@
     IEMOP_MNEMONIC(fptan_st0, "fptan st0");
     return FNIEMOP_CALL_1(iemOpHlpFpuReplace_st0_push, iemAImpl_fptan_r80_r80);
-}
-
-
-/**
- * Common worker for FPU instructions working on STn and ST0, storing the result
- * in STn, and popping the stack unless IE, DE or ZE was raised.
- *
- * @param   pfnAImpl    Pointer to the instruction implementation (assembly).
- */
-FNIEMOP_DEF_2(iemOpHlpFpu_stN_st0_pop, uint8_t, bRm, PFNIEMAIMPLFPUR80, pfnAImpl)
-{
-    IEMOP_HLP_DONE_DECODING_NO_LOCK_PREFIX();
-
-    IEM_MC_BEGIN(3, 1);
-    IEM_MC_LOCAL(IEMFPURESULT,          FpuRes);
-    IEM_MC_ARG_LOCAL_REF(PIEMFPURESULT, pFpuRes,        FpuRes,     0);
-    IEM_MC_ARG(PCRTFLOAT80U,            pr80Value1,                 1);
-    IEM_MC_ARG(PCRTFLOAT80U,            pr80Value2,                 2);
-
-    IEM_MC_MAYBE_RAISE_DEVICE_NOT_AVAILABLE();
-    IEM_MC_MAYBE_RAISE_FPU_XCPT();
-
-    IEM_MC_PREPARE_FPU_USAGE();
-    IEM_MC_IF_TWO_FPUREGS_NOT_EMPTY_REF_R80(pr80Value1, bRm & X86_MODRM_RM_MASK, pr80Value2, 0)
-        IEM_MC_CALL_FPU_AIMPL_3(pfnAImpl, pFpuRes, pr80Value1, pr80Value2);
-        IEM_MC_STORE_FPU_RESULT_THEN_POP(FpuRes, bRm & X86_MODRM_RM_MASK);
-    IEM_MC_ELSE()
-        IEM_MC_FPU_STACK_UNDERFLOW_THEN_POP(bRm & X86_MODRM_RM_MASK);
-    IEM_MC_ENDIF();
-    IEM_MC_ADVANCE_RIP();
-
-    IEM_MC_END();
-    return VINF_SUCCESS;
 }
 
@@ -14522,5 +14522,5 @@
     /* 0xef */  iemOp_Invalid,
     /* 0xf0 */  iemOp_f2xm1,
-    /* 0xf1 */  iemOp_fylx2,
+    /* 0xf1 */  iemOp_fyl2x,
     /* 0xf2 */  iemOp_fptan,
     /* 0xf3 */  iemOp_fpatan,
Index: /trunk/src/VBox/VMM/include/IEMInternal.h
===================================================================
--- /trunk/src/VBox/VMM/include/IEMInternal.h	(revision 65193)
+++ /trunk/src/VBox/VMM/include/IEMInternal.h	(revision 65194)
@@ -1340,4 +1340,5 @@
 
 FNIEMAIMPLFPUR80            iemAImpl_fpatan_r80_by_r80;
+FNIEMAIMPLFPUR80            iemAImpl_fyl2x_r80_by_r80;
 FNIEMAIMPLFPUR80            iemAImpl_fyl2xp1_r80_by_r80;
 
@@ -1359,5 +1360,4 @@
 FNIEMAIMPLFPUR80UNARY       iemAImpl_fchs_r80;
 FNIEMAIMPLFPUR80UNARY       iemAImpl_f2xm1_r80;
-FNIEMAIMPLFPUR80UNARY       iemAImpl_fyl2x_r80;
 FNIEMAIMPLFPUR80UNARY       iemAImpl_fsqrt_r80;
 FNIEMAIMPLFPUR80UNARY       iemAImpl_frndint_r80;
Index: /trunk/src/VBox/VMM/testcase/tstIEMCheckMc.cpp
===================================================================
--- /trunk/src/VBox/VMM/testcase/tstIEMCheckMc.cpp	(revision 65193)
+++ /trunk/src/VBox/VMM/testcase/tstIEMCheckMc.cpp	(revision 65194)
@@ -240,4 +240,5 @@
 
 #define iemAImpl_fpatan_r80_by_r80      NULL
+#define iemAImpl_fyl2x_r80_by_r80       NULL
 #define iemAImpl_fyl2xp1_r80_by_r80     NULL
 
@@ -249,5 +250,4 @@
 #define iemAImpl_fxam_r80               NULL
 #define iemAImpl_f2xm1_r80              NULL
-#define iemAImpl_fyl2x_r80              NULL
 #define iemAImpl_fsqrt_r80              NULL
 #define iemAImpl_frndint_r80            NULL