; $Id$

;; @file

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

;

;

; Copyright (C) 2006-2014 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 psz1 gcc: rdi msc: rcx x86:[esp+4]

; @param psz2 gcc: rsi msc: rdx x86:[esp+8]

; @param cch gcc: rdx msc: r8 x86:[esp+12]

RT_NOCRT_BEGINPROC strncmp

; input

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

%define psz1 rcx

%define psz2 rdx

%define cch r8

%else

%define psz1 rdi

%define psz2 rsi

%define cch rdx

%endif

%elifdef RT_ARCH_X86

mov ecx, [esp + 4]

mov edx, [esp + 8]

push ebx

mov ebx, [esp + 12+4]

%define psz1 ecx

%define psz2 edx

%define cch ebx

%else

%error "Unknown arch"

%endif

;

; The loop.

;

test cch, cch

jz .equal

.next:

mov al, [psz1]

mov ah, [psz2]

cmp al, ah

jne .not_equal

test al, al

jz .equal

dec cch

jz .equal

mov al, [psz1 + 1]

mov ah, [psz2 + 1]

cmp al, ah

jne .not_equal

test al, al

jz .equal

dec cch

jz .equal

mov al, [psz1 + 2]

mov ah, [psz2 + 2]

cmp al, ah

jne .not_equal

test al, al

jz .equal

dec cch

jz .equal

mov al, [psz1 + 3]

mov ah, [psz2 + 3]

cmp al, ah

jne .not_equal

test al, al

jz .equal

dec cch

jz .equal

add psz1, 4

add psz2, 4

jmp .next

.equal:

xor eax, eax

%ifdef RT_ARCH_X86

pop ebx

%endif

ret

.not_equal:

movzx ecx, ah

and eax, 0ffh

sub eax, ecx

%ifdef RT_ARCH_X86

pop ebx

%endif

ret

ENDPROC RT_NOCRT(strncmp)