MdePkg/Library/BaseLib/Ebc/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions on EBC.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. 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 UINT32
  16 EFIAPI
  17 InternalSyncCompareExchange32 (
  18   IN      volatile UINT32           *Value,
  19   IN      UINT32                    CompareValue,
  20   IN      UINT32                    ExchangeValue
  21   )
  22 {
  23   return *Value != CompareValue ? *Value :
  24            ((*Value = ExchangeValue), CompareValue);
  25 }
  26
  27 /**
  28   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  29
  30   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  31   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  32   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  33   The compare exchange operation must be performed using MP safe mechanisms.
  34
  35   @param  Value         A pointer to the 64-bit value for the compare exchange
  36                         operation.
  37   @param  CompareValue  64-bit value used in compare operation.
  38   @param  ExchangeValue 64-bit value used in exchange operation.
  39
  40   @return The original *Value before exchange.
  41
  42 **/
  43 UINT64
  44 EFIAPI
  45 InternalSyncCompareExchange64 (
  46   IN      volatile UINT64           *Value,
  47   IN      UINT64                    CompareValue,
  48   IN      UINT64                    ExchangeValue
  49   )
  50 {
  51   return *Value != CompareValue ? *Value :
  52            ((*Value = ExchangeValue), CompareValue);
  53 }
  54
  55 /**
  56   Performs an atomic increment of an 32-bit unsigned integer.
  57
  58   Performs an atomic increment of the 32-bit unsigned integer specified by
  59   Value and returns the incremented value. The increment operation must be
  60   performed using MP safe mechanisms. The state of the return value is not
  61   guaranteed to be MP safe.
  62
  63   @param  Value A pointer to the 32-bit value to increment.
  64
  65   @return The incremented value.
  66
  67 **/
  68 UINT32
  69 EFIAPI
  70 InternalSyncIncrement (
  71   IN      volatile UINT32           *Value
  72   )
  73 {
  74   return ++*Value;
  75 }
  76
  77 /**
  78   Performs an atomic decrement of an 32-bit unsigned integer.
  79
  80   Performs an atomic decrement of the 32-bit unsigned integer specified by
  81   Value and returns the decrement value. The decrement operation must be
  82   performed using MP safe mechanisms. The state of the return value is not
  83   guaranteed to be MP safe.
  84
  85   @param  Value A pointer to the 32-bit value to decrement.
  86
  87   @return The decrement value.
  88
  89 **/
  90 UINT32
  91 EFIAPI
  92 InternalSyncDecrement (
  93   IN      volatile UINT32           *Value
  94   )
  95 {
  96   return --*Value;
  97 }