; $Id$

;; @file

; IPRT - No-CRT memcmp - AMD64 & X86.

;

;

; Copyright (C) 2006-2007 Oracle Corporation

;

; This file is part of VirtualBox Open Source Edition (OSE), as

; available from http://www.virtualbox.org. This file is free software;

; you can redistribute it and/or modify it under the terms of the GNU

; General Public License (GPL) as published by the Free Software

; Foundation, in version 2 as it comes in the "COPYING" file of the

; VirtualBox OSE distribution. VirtualBox OSE is distributed in the

; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.

;

; The contents of this file may alternatively be used under the terms

; of the Common Development and Distribution License Version 1.0

; (CDDL) only, as it comes in the "COPYING.CDDL" file of the

; VirtualBox OSE 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.

;

%include "iprt/asmdefs.mac"

BEGINCODE

;;

; @param pv1 gcc: rdi msc: rcx x86:[esp+4]

; @param pv2 gcc: rsi msc: rdx x86:[esp+8]

; @param cb gcc: rdx msc: r8 x86:[esp+0ch]

RT_NOCRT_BEGINPROC memcmp

cld

xor eax, eax

; 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

repe cmpsq

jne .not_equal_qword

%else

push edi

push esi

mov ecx, [esp + 0ch + 8]

mov edi, [esp + 04h + 8]

mov esi, [esp + 08h + 8]

mov edx, ecx

jecxz .done

shr ecx, 2

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

.not_equal_byte:

repe cmpsb

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)