1 files changed, 70 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/asm/ASMAtomicXchgU64.asm b/src/VBox/Runtime/common/asm/ASMAtomicXchgU64.asm
new file mode 100644
index 00000000..1eafc832
--- /dev/null
+++ b/src/VBox/Runtime/common/asm/ASMAtomicXchgU64.asm
@@ -0,0 +1,70 @@
+; $Id: ASMAtomicXchgU64.asm $
+;; @file
+; IPRT - ASMAtomicXchgU64().
+;
+
+;
+; 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
+
+;;
+; 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 Current (i.e. old) *pu64 value (x86:eax:edx, 64-bit: rax)
+;
+BEGINPROC_EXPORTED ASMAtomicXchgU64
+%ifdef RT_ARCH_AMD64
+ %ifdef ASM_CALL64_MSC
+        xchg    [rcx], rdx
+ %else
+        xchg    [rdi], rsi
+ %endif
+        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
+