MdePkg/Library/BaseSynchronizationLib/X64/InterlockedDecrement.c

   1 /** @file
   2   InterlockedDecrement function
   3
   4   Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 /**
  16   Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  17 **/
  18
  19 long _InterlockedDecrement(
  20    long * lpAddend
  21 );
  22
  23 #pragma intrinsic(_InterlockedDecrement)
  24
  25 /**
  26   Performs an atomic decrement of an 32-bit unsigned integer.
  27
  28   Performs an atomic decrement of the 32-bit unsigned integer specified by
  29   Value and returns the decrement value. The decrement operation must be
  30   performed using MP safe mechanisms. The state of the return value is not
  31   guaranteed to be MP safe.
  32
  33   @param  Value A pointer to the 32-bit value to decrement.
  34
  35   @return The decrement value.
  36
  37 **/
  38 UINT32
  39 EFIAPI
  40 InternalSyncDecrement (
  41   IN      volatile UINT32           *Value
  42   )
  43 {
  44   return _InterlockedDecrement ((long *)(UINTN)(Value));
  45 }
  46