MdePkg/BaseSynchronizationLib: Add InterlockedCompareExchange16

This implements the function InterlockedCompareExchange16 () for all
architectures, using architecture and toolchain specific intrinsics
or primitive assembler instructions.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Michael Kinney <michael.d.kinney@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16966 6f19259b-4bc3-4df7-8a09-765794883524

3 files changed, 139 insertions, 0 deletions

diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
index b5a7827fc0..bd81aad6c2 100644
--- a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
+++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
@@ -88,6 +88,48 @@ InternalSyncDecrement (
 }

 

 /**

+  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

+InternalSyncCompareExchange16 (

+  IN OUT volatile  UINT16           *Value,

+  IN      UINT16                    CompareValue,

+  IN      UINT16                    ExchangeValue

+  )

+{

+

+  __asm__ __volatile__ (

+    "                     \n\t"

+    "lock                 \n\t"

+    "cmpxchgw    %1, %2   \n\t"

+    : "=a" (CompareValue)

+    : "q"  (ExchangeValue),

+      "m"  (*Value),

+      "0"  (CompareValue)

+    : "memory",

+      "cc"

+    );

+

+  return CompareValue;

+}

+

+/**

   Performs an atomic compare exchange operation on a 32-bit unsigned integer.

 

   Performs an atomic compare exchange operation on the 32-bit unsigned integer

diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.asm b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.asm
new file mode 100644
index 0000000000..7d14e8e830
--- /dev/null
+++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.asm
@@ -0,0 +1,46 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2015, Linaro Ltd. 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:
+;
+;------------------------------------------------------------------------------
+
+    .486
+    .model  flat,C
+    .code
+
+;------------------------------------------------------------------------------
+; UINT16
+; EFIAPI
+; InternalSyncCompareExchange16 (
+;   IN      UINT16                    *Value,
+;   IN      UINT16                    CompareValue,
+;   IN      UINT16                    ExchangeValue
+;   );
+;------------------------------------------------------------------------------
+InternalSyncCompareExchange16   PROC
+    mov     ecx, [esp + 4]
+    mov     ax, [esp + 8]
+    mov     dx, [esp + 12]
+    lock    cmpxchg [ecx], dx
+    ret
+InternalSyncCompareExchange16   ENDP
+
+    END
diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c
new file mode 100644
index 0000000000..102173b11e
--- /dev/null
+++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c
@@ -0,0 +1,51 @@
+/** @file
+  InterlockedCompareExchange16 function
+
+  Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2015, Linaro Ltd. 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.
+
+**/
+
+
+
+
+/**
+  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
+InternalSyncCompareExchange16 (
+  IN      UINT16                    *Value,
+  IN      UINT16                    CompareValue,
+  IN      UINT16                    ExchangeValue
+  )
+{
+  _asm {
+    mov     ecx, Value
+    mov     ax, CompareValue
+    mov     dx, ExchangeValue
+    lock    cmpxchg [ecx], dx
+  }
+}
+