This is a copy of InterlockedCompareExchange32 from the
BaseSynchronizationLib.
The function will be used in the next patch.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.per...@citrix.com>
---
Change in V2:
- Add intel compilation code
MSFT code is not compied over because I don't know how it works.
---
OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h | 15 ++++++++
.../XenBusDxe/InterlockedCompareExchange16Intel.c | 32 +++++++++++++++++
.../XenBusDxe/X64/InterlockedCompareExchange16.asm | 41 ++++++++++++++++++++++
.../XenBusDxe/X64/InterlockedCompareExchange16.c | 41 ++++++++++++++++++++++
OvmfPkg/XenBusDxe/XenBusDxe.inf | 4 +++
5 files changed, 133 insertions(+)
create mode 100644 OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
create mode 100644 OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
create mode 100644 OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
create mode 100644 OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
new file mode 100644
index 0000000..9067882
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16.h
@@ -0,0 +1,15 @@
+UINT16
+EFIAPI
+InternalSyncCompareExchange16 (
+ IN UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ );
+
+UINT16
+EFIAPI
+InterlockedCompareExchange16 (
+ IN OUT volatile UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ );
diff --git a/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
new file mode 100644
index 0000000..bb40e70
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/InterlockedCompareExchange16Intel.c
@@ -0,0 +1,32 @@
+#include "InterlockedCompareExchange16.h"
+
+/**
+ Performs an atomic compare exchange operation on a 16-bit unsigned integer.
+
+ Performs an atomic compare exchange operation on the 16-bit unsigned integer
+ specified by Value. If Value is equal to CompareValue, then Value is set to
+ ExchangeValue and CompareValue is returned. If Value is not equal to
CompareValue,
+ then Value is returned. The compare exchange operation must be performed
using
+ MP safe mechanisms.
+
+ If Value is NULL, then ASSERT().
+
+ @param Value A pointer to the 16-bit value for the compare exchange
+ operation.
+ @param CompareValue 16-bit value used in compare operation.
+ @param ExchangeValue 16-bit value used in exchange operation.
+
+ @return The original *Value before exchange.
+
+**/
+UINT16
+EFIAPI
+InterlockedCompareExchange16 (
+ IN OUT UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ )
+{
+ ASSERT (Value != NULL);
+ return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);
+}
diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
new file mode 100644
index 0000000..b23e421
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.asm
@@ -0,0 +1,41 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; This program and the accompanying materials
+; are licensed and made available under the terms and conditions of the BSD
License
+; which accompanies this distribution. The full text of the license may be
found at
+; http://opensource.org/licenses/bsd-license.php.
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+; Module Name:
+;
+; InterlockedCompareExchange16.Asm
+;
+; Abstract:
+;
+; InterlockedCompareExchange16 function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+ .code
+
+;------------------------------------------------------------------------------
+; UINT16
+; EFIAPI
+; InterlockedCompareExchange16 (
+; IN UINT16 *Value,
+; IN UINT16 CompareValue,
+; IN UINT16 ExchangeValue
+; );
+;------------------------------------------------------------------------------
+InternalSyncCompareExchange16 PROC
+ mov eax, edx
+ lock cmpxchg [rcx], r8w
+ ret
+InternalSyncCompareExchange16 ENDP
+
+ END
diff --git a/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
new file mode 100644
index 0000000..64962ba
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/X64/InterlockedCompareExchange16.c
@@ -0,0 +1,41 @@
+// Took from BaseSynchronizationLib, and replaced 32 by 16
+/**
+ Performs an atomic compare exchange operation on a 16-bit unsigned integer.
+
+ Performs an atomic compare exchange operation on the 16-bit unsigned integer
+ specified by Value. If Value is equal to CompareValue, then Value is set to
+ ExchangeValue and CompareValue is returned. If Value is not equal to
CompareValue,
+ then Value is returned. The compare exchange operation must be performed
using
+ MP safe mechanisms.
+
+
+ @param Value A pointer to the 16-bit value for the compare exchange
+ operation.
+ @param CompareValue 16-bit value used in compare operation.
+ @param ExchangeValue 16-bit value used in exchange operation.
+
+ @return The original *Value before exchange.
+
+**/
+UINT16
+EFIAPI
+InterlockedCompareExchange16 (
+ IN OUT volatile UINT16 *Value,
+ IN UINT16 CompareValue,
+ IN UINT16 ExchangeValue
+ )
+{
+ __asm__ __volatile__ (
+ "lock \n\t"
+ "cmpxchgw %3, %1 "
+ : "=a" (CompareValue), // %0
+ "=m" (*Value) // %1
+ : "a" (CompareValue), // %2
+ "r" (ExchangeValue), // %3
+ "m" (*Value)
+ : "memory",
+ "cc"
+ );
+
+ return CompareValue;
+}
diff --git a/OvmfPkg/XenBusDxe/XenBusDxe.inf b/OvmfPkg/XenBusDxe/XenBusDxe.inf
index aed2359..612c3db 100644
--- a/OvmfPkg/XenBusDxe/XenBusDxe.inf
+++ b/OvmfPkg/XenBusDxe/XenBusDxe.inf
@@ -33,10 +33,14 @@
ComponentName.h
XenHypercall.c
XenHypercall.h
+ InterlockedCompareExchange16.h
[Sources.X64]
X64/hypercall.S
X64/hypercall.asm
+ X64/InterlockedCompareExchange16.c | GCC
+ X64/InterlockedCompareExchange16.asm | INTEL
+ InterlockedCompareExchange16Intel.c | INTEL
[LibraryClasses]
UefiDriverEntryPoint
--
Anthony PERARD
------------------------------------------------------------------------------
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