| 1 | ; $Id: fegetround.asm 98103 2023-01-17 14:15:46Z vboxsync $
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| 2 | ;; @file
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| 3 | ; IPRT - No-CRT fegetround - AMD64 & X86.
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2022-2023 Oracle and/or its affiliates.
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| 8 | ;
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| 9 | ; This file is part of VirtualBox base platform packages, as
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| 10 | ; available from https://www.virtualbox.org.
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| 11 | ;
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| 12 | ; This program is free software; you can redistribute it and/or
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| 13 | ; modify it under the terms of the GNU General Public License
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| 14 | ; as published by the Free Software Foundation, in version 3 of the
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| 15 | ; License.
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| 16 | ;
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| 17 | ; This program is distributed in the hope that it will be useful, but
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| 18 | ; WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | ; General Public License for more details.
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| 21 | ;
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| 22 | ; You should have received a copy of the GNU General Public License
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| 23 | ; along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | ;
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| 25 | ; The contents of this file may alternatively be used under the terms
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| 26 | ; of the Common Development and Distribution License Version 1.0
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| 27 | ; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | ; in the VirtualBox distribution, in which case the provisions of the
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| 29 | ; CDDL are applicable instead of those of the GPL.
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| 30 | ;
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| 31 | ; You may elect to license modified versions of this file under the
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| 32 | ; terms and conditions of either the GPL or the CDDL or both.
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| 33 | ;
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| 34 | ; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | ;
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| 36 |
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| 37 |
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| 38 | %define RT_ASM_WITH_SEH64
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| 39 | %include "iprt/asmdefs.mac"
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| 40 | %include "iprt/x86.mac"
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| 41 |
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| 42 |
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| 43 | BEGINCODE
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| 44 |
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| 45 | ;;
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| 46 | ; Gets the hardware rounding mode.
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| 47 | ; @returns eax x87 rounding mask (X86_FCW_RC_MASK)
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| 48 | ;
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| 49 | RT_NOCRT_BEGINPROC fegetround
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| 50 | push xBP
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| 51 | SEH64_PUSH_xBP
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| 52 | mov xBP, xSP
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| 53 | SEH64_SET_FRAME_xBP 0
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| 54 | sub xSP, 10h
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| 55 | SEH64_ALLOCATE_STACK 10h
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| 56 | SEH64_END_PROLOGUE
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| 57 |
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| 58 | ;
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| 59 | ; Save control word and isolate the rounding mode.
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| 60 | ;
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| 61 | ; On 64-bit we'll use the MXCSR since the windows compiler/CRT doesn't
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| 62 | ; necessarily keep them in sync. We'll still return the x87-style flags.
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| 63 | ;
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| 64 | %ifdef RT_ARCH_AMD64
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| 65 | stmxcsr [xBP - 10h]
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| 66 | mov eax, [xBP - 10h]
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| 67 | and eax, X86_MXCSR_RC_MASK
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| 68 | shr eax, X86_MXCSR_RC_SHIFT - X86_FCW_RC_SHIFT
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| 69 | %else
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| 70 | fstcw [xBP - 10h]
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| 71 | movzx eax, word [xBP - 10h]
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| 72 | and eax, X86_FCW_RC_MASK
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| 73 | %endif
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| 74 |
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| 75 | .return_val:
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| 76 | leave
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| 77 | ret
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| 78 | ENDPROC RT_NOCRT(fegetround)
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| 79 |
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