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|
; $Id: memcmp.asm $
;; @file
; IPRT - No-CRT memcmp - AMD64 & X86.
;
;
; Copyright (C) 2006-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox 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.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
%include "iprt/asmdefs.mac"
BEGINCODE
;;
; @param pv1 gcc: rdi msc: rcx x86:[esp+4] wcall: eax
; @param pv2 gcc: rsi msc: rdx x86:[esp+8] wcall: edx
; @param cb gcc: rdx msc: r8 x86:[esp+0ch] wcall: ebx
RT_NOCRT_BEGINPROC memcmp
cld
; Do the bulk of the work.
%ifdef RT_ARCH_AMD64
%ifdef ASM_CALL64_MSC
mov r10, rdi ; save
mov r11, rsi ; save
mov rdi, rcx
mov rsi, rdx
mov rcx, r8
mov rdx, r8
%else
mov rcx, rdx
%endif
shr rcx, 3
xor eax, eax
repe cmpsq
jne .not_equal_qword
%else
push edi
push esi
%ifdef ASM_CALL32_WATCOM
mov edi, eax
mov esi, edx
mov ecx, ebx
mov edx, ebx
%else
mov ecx, [esp + 0ch + 8]
mov edi, [esp + 04h + 8]
mov esi, [esp + 08h + 8]
mov edx, ecx
%endif
jecxz .done
shr ecx, 2
xor eax, eax
repe cmpsd
jne .not_equal_dword
%endif
; The remaining bytes.
%ifdef RT_ARCH_AMD64
test dl, 4
jz .dont_cmp_dword
cmpsd
jne .not_equal_dword
%endif
.dont_cmp_dword:
test dl, 2
jz .dont_cmp_word
cmpsw
jne .not_equal_word
.dont_cmp_word:
test dl, 1
jz .dont_cmp_byte
cmpsb
jne .not_equal_byte
.dont_cmp_byte:
.done:
%ifdef RT_ARCH_AMD64
%ifdef ASM_CALL64_MSC
mov rdi, r10
mov rsi, r11
%endif
%else
pop esi
pop edi
%endif
ret
;
; Mismatches.
;
%ifdef RT_ARCH_AMD64
.not_equal_qword:
mov ecx, 8
sub rsi, 8
sub rdi, 8
repe cmpsb
.not_equal_byte:
mov al, [xDI-1]
movzx ecx, byte [xSI-1]
sub eax, ecx
jmp .done
%endif
.not_equal_dword:
mov ecx, 4
sub xSI, 4
sub xDI, 4
repe cmpsb
%ifdef RT_ARCH_AMD64
jmp .not_equal_byte
%else
.not_equal_byte:
mov al, [xDI-1]
movzx ecx, byte [xSI-1]
sub eax, ecx
jmp .done
%endif
.not_equal_word:
mov ecx, 2
sub xSI, 2
sub xDI, 2
repe cmpsb
jmp .not_equal_byte
ENDPROC RT_NOCRT(memcmp)
|
