; $Id$

;; @file

; IPRT - ASMAtomicXchgU64().

;

;

; 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.

;

;*******************************************************************************

;* Header Files *

;*******************************************************************************

%include "iprt/asmdefs.mac"

BEGINCODE

;;

; Atomically Exchange an unsigned 64-bit value, ordered.

;

; @param pu64 x86:ebp+8 gcc:rdi msc:rcx

; @param u64New x86:ebp+c gcc:rsi msc:rdx

;

; @returns bool result: true if successfully exchanged, false if not.

; x86:al

;

BEGINPROC_EXPORTED ASMAtomicXchgU64

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

mov rax, r8

.try_again:

lock cmpxchg [rcx], rdx

%else

.try_again:

mov rax, rcx

lock cmpxchg [rdi], rsi

%endif

jnz .try_again

ret

%endif

%ifdef RT_ARCH_X86

push ebp

mov ebp, esp

push ebx

push edi

.try_again:

mov ebx, dword [ebp+0ch]

mov ecx, dword [ebp+0ch + 4]

mov edi, [ebp+08h]

lock cmpxchg8b [edi]

jnz .try_again

pop edi

pop ebx

leave

ret

%endif

ENDPROC ASMAtomicXchgU64