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Diffstat (limited to 'src/VBox/Runtime/common/string/memcmp.asm')
| -rw-r--r-- | src/VBox/Runtime/common/string/memcmp.asm | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/string/memcmp.asm b/src/VBox/Runtime/common/string/memcmp.asm new file mode 100644 index 00000000..3c8b1974 --- /dev/null +++ b/src/VBox/Runtime/common/string/memcmp.asm @@ -0,0 +1,155 @@ +; $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) + |