; $Id$

;; @file

; IPRT - ASMAtomicReadU64().

;

;

; 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 reads 64-bit value.

;

; @param pu64 x86:ebp+8

;

; @returns The current value. (x86:eax+edx)

;

;

BEGINPROC_EXPORTED ASMAtomicReadU64

%ifdef RT_ARCH_AMD64

mfence ; ASSUME its present.

%ifdef ASM_CALL64_MSC

mov rax, [rcx]

%else

mov rax, [rdi]

%endif

ret

%endif

%ifdef RT_ARCH_X86

push ebp

mov ebp, esp

push ebx

push edi

xor eax, eax

xor edx, edx

mov edi, [ebp+08h]

xor ecx, ecx

xor ebx, ebx

lock cmpxchg8b [edi]

pop edi

pop ebx

leave

ret

%endif

ENDPROC ASMAtomicReadU64