MdePkg/Library/BaseSynchronizationLib/Arm/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions. Still needs to be ported
   3
   4   Copyright (c) 2006 - 2010, Intel Corporation<BR>
   5   Portions copyright (c) 2008-2009 Apple Inc. All rights reserved.<BR>
   6   All rights reserved. This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 /**
  17   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  18
  19   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  20   specified by Value.  If Value is equal to CompareValue, then Value is set to
  21   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  22   then Value is returned.  The compare exchange operation must be performed using
  23   MP safe mechanisms.
  24
  25   @param  Value         A pointer to the 32-bit value for the compare exchange
  26                         operation.
  27   @param  CompareValue  32-bit value used in compare operation.
  28   @param  ExchangeValue 32-bit value used in exchange operation.
  29
  30   @return The original *Value before exchange.
  31
  32 **/
  33 UINT32
  34 EFIAPI
  35 InternalSyncCompareExchange32 (
  36   IN      volatile UINT32           *Value,
  37   IN      UINT32                    CompareValue,
  38   IN      UINT32                    ExchangeValue
  39   )
  40 {
  41   return *Value != CompareValue ? *Value :
  42            ((*Value = ExchangeValue), CompareValue);
  43 }
  44
  45 /**
  46   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  47
  48   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  49   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  50   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  51   The compare exchange operation must be performed using MP safe mechanisms.
  52
  53   @param  Value         A pointer to the 64-bit value for the compare exchange
  54                         operation.
  55   @param  CompareValue  64-bit value used in compare operation.
  56   @param  ExchangeValue 64-bit value used in exchange operation.
  57
  58   @return The original *Value before exchange.
  59
  60 **/
  61 UINT64
  62 EFIAPI
  63 InternalSyncCompareExchange64 (
  64   IN      volatile UINT64           *Value,
  65   IN      UINT64                    CompareValue,
  66   IN      UINT64                    ExchangeValue
  67   )
  68 {
  69   return *Value != CompareValue ? *Value :
  70            ((*Value = ExchangeValue), CompareValue);
  71 }
  72
  73 /**
  74   Performs an atomic increment of an 32-bit unsigned integer.
  75
  76   Performs an atomic increment of the 32-bit unsigned integer specified by
  77   Value and returns the incremented value. The increment operation must be
  78   performed using MP safe mechanisms. The state of the return value is not
  79   guaranteed to be MP safe.
  80
  81   @param  Value A pointer to the 32-bit value to increment.
  82
  83   @return The incremented value.
  84
  85 **/
  86 UINT32
  87 EFIAPI
  88 InternalSyncIncrement (
  89   IN      volatile UINT32           *Value
  90   )
  91 {
  92   return ++*Value;
  93 }
  94
  95 /**
  96   Performs an atomic decrement of an 32-bit unsigned integer.
  97
  98   Performs an atomic decrement of the 32-bit unsigned integer specified by
  99   Value and returns the decrement value. The decrement operation must be
 100   performed using MP safe mechanisms. The state of the return value is not
 101   guaranteed to be MP safe.
 102
 103   @param  Value A pointer to the 32-bit value to decrement.
 104
 105   @return The decrement value.
 106
 107 **/
 108 UINT32
 109 EFIAPI
 110 InternalSyncDecrement (
 111   IN      volatile UINT32           *Value
 112   )
 113 {
 114   return --*Value;
 115 }