1 files changed, 60 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/asm/ASMAtomicXchgU16.asm b/src/VBox/Runtime/common/asm/ASMAtomicXchgU16.asm
new file mode 100644
index 00000000..c361f2a1
--- /dev/null
+++ b/src/VBox/Runtime/common/asm/ASMAtomicXchgU16.asm
@@ -0,0 +1,60 @@
+; $Id: ASMAtomicXchgU16.asm $
+;; @file
+; IPRT - ASMAtomicXchgU16().
+;
+
+;
+; 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 16-bit value, ordered.
+;
+; @param    pu16     x86:ebp+8   gcc:rdi  msc:rcx
+; @param    u16New   x86:ebp+c   gcc:si   msc:dx
+;
+; @returns Current (i.e. old) *pu16 value (AX).
+;
+BEGINPROC_EXPORTED ASMAtomicXchgU16
+%ifdef RT_ARCH_AMD64
+ %ifdef ASM_CALL64_MSC
+        mov     ax, dx
+        xchg    [rcx], ax
+ %else
+        mov     ax, si
+        xchg    [rdi], ax
+ %endif
+%elifdef RT_ARCH_X86
+        mov     ecx, [esp+04h]
+        mov     ax, [esp+08h]
+        xchg    [ecx], ax
+%else
+ %error "Unsupport arch."
+%endif
+        ret
+ENDPROC ASMAtomicXchgU16
+