source: vbox/trunk/src/VBox/Runtime/win/amd64/ASMAtomicXchgU8.asm@ 76553

;; @file
; IPRT - ASMAtomicXchgU8().
;

;
; Copyright (C) 2006-2019 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

;;
; @returns al Current *pu8 value
; @param   rcx  pu8    Pointer to the 8-bit variable to update.
; @param   dl   u8     The 8-bit value to assign to *pu8.
BEGINPROC_EXPORTED ASMAtomicXchgU8
        xchg    [rcx], dl
        movzx   eax, dl
        ret
ENDPROC ASMAtomicXchgU8