MdePkg/Library/BaseSynchronizationLib/Arm/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions. Still needs to be ported
   3
   4   Copyright (c) 2006 - 2009, 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 UINT32
  17 EFIAPI
  18 InternalSyncCompareExchange32 (
  19   IN      volatile UINT32           *Value,
  20   IN      UINT32                    CompareValue,
  21   IN      UINT32                    ExchangeValue
  22   )
  23 {
  24   return *Value != CompareValue ? *Value :
  25            ((*Value = ExchangeValue), CompareValue);
  26 }
  27
  28 /**
  29   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  30
  31   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  32   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  33   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  34   The compare exchange operation must be performed using MP safe mechanisms.
  35
  36   @param  Value         A pointer to the 64-bit value for the compare exchange
  37                         operation.
  38   @param  CompareValue  64-bit value used in compare operation.
  39   @param  ExchangeValue 64-bit value used in exchange operation.
  40
  41   @return The original *Value before exchange.
  42
  43 **/
  44 UINT64
  45 EFIAPI
  46 InternalSyncCompareExchange64 (
  47   IN      volatile UINT64           *Value,
  48   IN      UINT64                    CompareValue,
  49   IN      UINT64                    ExchangeValue
  50   )
  51 {
  52   return *Value != CompareValue ? *Value :
  53            ((*Value = ExchangeValue), CompareValue);
  54 }
  55
  56 /**
  57   Performs an atomic increment of an 32-bit unsigned integer.
  58
  59   Performs an atomic increment of the 32-bit unsigned integer specified by
  60   Value and returns the incremented value. The increment operation must be
  61   performed using MP safe mechanisms. The state of the return value is not
  62   guaranteed to be MP safe.
  63
  64   @param  Value A pointer to the 32-bit value to increment.
  65
  66   @return The incremented value.
  67
  68 **/
  69 UINT32
  70 EFIAPI
  71 InternalSyncIncrement (
  72   IN      volatile UINT32           *Value
  73   )
  74 {
  75   return ++*Value;
  76 }
  77
  78 /**
  79   Performs an atomic decrement of an 32-bit unsigned integer.
  80
  81   Performs an atomic decrement of the 32-bit unsigned integer specified by
  82   Value and returns the decrement value. The decrement operation must be
  83   performed using MP safe mechanisms. The state of the return value is not
  84   guaranteed to be MP safe.
  85
  86   @param  Value A pointer to the 32-bit value to decrement.
  87
  88   @return The decrement value.
  89
  90 **/
  91 UINT32
  92 EFIAPI
  93 InternalSyncDecrement (
  94   IN      volatile UINT32           *Value
  95   )
  96 {
  97   return --*Value;
  98 }