EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseLib/Ipf/Synchronization.c

   1 /*++
   2
   3 Copyright (c) 2004 - 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12
  13 Module Name:
  14
  15   Synchronization.c
  16
  17 Abstract:
  18
  19 --*/
  20
  21 #include "..\BaseLibInternal.h"
  22
  23 /**
  24   Performs an atomic increment of an 32-bit unsigned integer.
  25
  26   Performs an atomic increment of the 32-bit unsigned integer specified by
  27   Value and returns the incremented value. The increment operation must be
  28   performed using MP safe mechanisms. The state of the return value is not
  29   guaranteed to be MP safe.
  30
  31   @param  Value A pointer to the 32-bit value to increment.
  32
  33   @return The incremented value.
  34
  35 **/
  36 UINT32
  37 EFIAPI
  38 InternalSyncIncrement (
  39   IN      volatile UINT32           *Value
  40   )
  41 {
  42   UINT32                            OriginalValue;
  43
  44   do {
  45     OriginalValue = *Value;
  46   } while (OriginalValue != InternalSyncCompareExchange32 (
  47                               Value,
  48                               OriginalValue,
  49                               OriginalValue + 1
  50                               ));
  51   return OriginalValue + 1;
  52 }
  53
  54 /**
  55   Performs an atomic decrement of an 32-bit unsigned integer.
  56
  57   Performs an atomic decrement of the 32-bit unsigned integer specified by
  58   Value and returns the decrement value. The decrement operation must be
  59   performed using MP safe mechanisms. The state of the return value is not
  60   guaranteed to be MP safe.
  61
  62   @param  Value A pointer to the 32-bit value to decrement.
  63
  64   @return The decrement value.
  65
  66 **/
  67 UINT32
  68 EFIAPI
  69 InternalSyncDecrement (
  70   IN      volatile UINT32           *Value
  71   )
  72 {
  73   UINT32                            OriginalValue;
  74
  75   do {
  76     OriginalValue = *Value;
  77   } while (OriginalValue != InternalSyncCompareExchange32 (
  78                               Value,
  79                               OriginalValue,
  80                               OriginalValue - 1
  81                               ));
  82   return OriginalValue - 1;
  83 }