| 1 | ; $Id: x86-allmul.asm 98495 2023-02-07 15:56:13Z vboxsync $
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| 2 | ;; @file
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| 3 | ; IPRT - Visual C++ Compiler - 64-bit multiplication support, x86.
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 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 | ;*********************************************************************************************************************************
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| 39 | ;* Header Files *
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| 40 | ;*********************************************************************************************************************************
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| 41 | %include "iprt/asmdefs.mac"
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| 42 |
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| 43 |
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| 44 | ;;
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| 45 | ; Multiplication of signed or unsigned 64-bit values.
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| 46 | ;
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| 47 | ; @returns edx:eax
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| 48 | ; @param [esp+04h] Factor #1 (64-bit)
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| 49 | ; @param [esp+0ch] Factor #2 (64-bit)
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| 50 | ; @uses ecx
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| 51 | ;
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| 52 | BEGINPROC_RAW __allmul
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| 53 | ;
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| 54 | ; See if this is a pure 32-bit multiplication. We might get lucky.
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| 55 | ;
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| 56 | mov eax, [esp + 04h] ; eax = F1.lo
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| 57 |
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| 58 | mov edx, [esp + 04h+4]
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| 59 | mov ecx, [esp + 0ch+4] ; ecx = F2.hi
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| 60 | or edx, ecx ; trashes edx but reduces number of branches.
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| 61 | jnz .complicated
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| 62 |
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| 63 | ; edx:eax = F1.lo * F2.lo
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| 64 | mul dword [esp + 0ch]
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| 65 |
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| 66 | ret 10h
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| 67 |
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| 68 | ;
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| 69 | ; Complicated.
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| 70 | ;
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| 71 | .complicated:
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| 72 | ; ecx = F1.lo * F2.hi (edx contains overflow here can be ignored)
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| 73 | mul ecx
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| 74 | mov ecx, eax
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| 75 |
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| 76 | ; ecx += F1.hi * F2.lo (edx can be ignored again)
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| 77 | mov eax, [esp + 04h+4]
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| 78 | mul dword [esp + 0ch]
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| 79 | add ecx, eax
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| 80 |
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| 81 | ; edx:eax = F1.lo * F2.lo
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| 82 | mov eax, [esp + 04h]
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| 83 | mul dword [esp + 0ch]
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| 84 |
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| 85 | ; Add ecx to the high part (edx).
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| 86 | add edx, ecx
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| 87 |
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| 88 | ret 10h
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| 89 | ENDPROC_RAW __allmul
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| 90 |
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