; $Id$

;; @file

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

;

;

; Copyright (C) 2006-2010 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 pv gcc: rdi msc: ecx x86:[esp+4]

; @param ch gcc: esi msc: edx x86:[esp+8]

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

RT_NOCRT_BEGINPROC memchr

cld

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

or r8, r8

jz .not_found_early

mov r9, rdi ; save rdi

mov eax, edx

mov rdi, rcx

mov rcx, r8

%else

mov rcx, rdx

jrcxz .not_found_early

mov eax, esi

%endif

%else

mov ecx, [esp + 0ch]

jecxz .not_found_early

mov edx, edi ; save edi

mov eax, [esp + 8]

mov edi, [esp + 4]

%endif

; do the search

repne scasb

jne .not_found

; found it

lea xAX, [xDI - 1]

%ifdef ASM_CALL64_MSC

mov rdi, r9

%endif

%ifdef RT_ARCH_X86

mov edi, edx

%endif

ret

.not_found:

%ifdef ASM_CALL64_MSC

mov rdi, r9

%endif

%ifdef RT_ARCH_X86

mov edi, edx

%endif

.not_found_early:

xor eax, eax

ret

ENDPROC RT_NOCRT(memchr)