MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c

   1 /** @file
   2   GCC inline implementation of BaseSynchronizationLib processor specific functions.
   3
   4   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   5   Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   6   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
  18 /**
  19   Performs an atomic increment of an 32-bit unsigned integer.
  20
  21   Performs an atomic increment of the 32-bit unsigned integer specified by
  22   Value and returns the incremented value. The increment operation must be
  23   performed using MP safe mechanisms. The state of the return value is not
  24   guaranteed to be MP safe.
  25
  26   @param  Value A pointer to the 32-bit value to increment.
  27
  28   @return The incremented value.
  29
  30 **/
  31 UINT32
  32 EFIAPI
  33 InternalSyncIncrement (
  34   IN      volatile UINT32    *Value
  35   )
  36 {
  37   UINT32  Result;
  38
  39   __asm__ __volatile__ (
  40     "lock               \n\t"
  41     "incl    %2         \n\t"
  42     "movl    %2, %%eax      "
  43     : "=a" (Result),          // %0
  44       "=m" (*Value)           // %1
  45     : "m"  (*Value)           // %2
  46     : "memory",
  47       "cc"
  48     );
  49
  50   return Result;
  51
  52 }
  53
  54
  55 /**
  56   Performs an atomic decrement of an 32-bit unsigned integer.
  57
  58   Performs an atomic decrement of the 32-bit unsigned integer specified by
  59   Value and returns the decremented value. The decrement 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 decrement.
  64
  65   @return The decremented value.
  66
  67 **/
  68 UINT32
  69 EFIAPI
  70 InternalSyncDecrement (
  71   IN      volatile UINT32       *Value
  72   )
  73 {
  74    UINT32  Result;
  75
  76   __asm__ __volatile__ (
  77     "lock               \n\t"
  78     "decl    %2         \n\t"
  79     "movl    %2, %%eax      "
  80     : "=a" (Result),          // %0
  81       "=m" (*Value)           // %1
  82     : "m"  (*Value)           // %2
  83     : "memory",
  84       "cc"
  85     );
  86
  87   return Result;
  88 }
  89
  90 /**
  91   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  92
  93   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  94   specified by Value.  If Value is equal to CompareValue, then Value is set to
  95   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  96   then Value is returned.  The compare exchange operation must be performed using
  97   MP safe mechanisms.
  98
  99
 100   @param  Value         A pointer to the 32-bit value for the compare exchange
 101                         operation.
 102   @param  CompareValue  32-bit value used in compare operation.
 103   @param  ExchangeValue 32-bit value used in exchange operation.
 104
 105   @return The original *Value before exchange.
 106
 107 **/
 108 UINT32
 109 EFIAPI
 110 InternalSyncCompareExchange32 (
 111   IN OUT volatile  UINT32           *Value,
 112   IN      UINT32                    CompareValue,
 113   IN      UINT32                    ExchangeValue
 114   )
 115 {
 116
 117   __asm__ __volatile__ (
 118     "                     \n\t"
 119     "lock                 \n\t"
 120     "cmpxchgl    %1, %2   \n\t"
 121     : "=a" (CompareValue)     // %0
 122     : "q"  (ExchangeValue),   // %1
 123       "m"  (*Value),          // %2
 124       "0"  (CompareValue)     // %4
 125     : "memory",
 126       "cc"
 127     );
 128
 129   return CompareValue;
 130 }
 131
 132 /**
 133   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 134
 135   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 136   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 137   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 138   The compare exchange operation must be performed using MP safe mechanisms.
 139
 140
 141   @param  Value         A pointer to the 64-bit value for the compare exchange
 142                         operation.
 143   @param  CompareValue  64-bit value used in compare operation.
 144   @param  ExchangeValue 64-bit value used in exchange operation.
 145
 146   @return The original *Value before exchange.
 147
 148 **/
 149 UINT64
 150 EFIAPI
 151 InternalSyncCompareExchange64 (
 152   IN OUT  volatile UINT64           *Value,
 153   IN      UINT64                    CompareValue,
 154   IN      UINT64                    ExchangeValue
 155   )
 156 {
 157   __asm__ __volatile__ (
 158     "                       \n\t"
 159     "push        %%ebx      \n\t"
 160     "movl        %2,%%ebx   \n\t"
 161     "lock                   \n\t"
 162     "cmpxchg8b   (%1)       \n\t"
 163     "pop         %%ebx      \n\t"
 164     : "+A"  (CompareValue)                    // %0
 165     : "S"   (Value),                          // %1
 166       "r"   ((UINT32) ExchangeValue),         // %2
 167       "c"   ((UINT32) (ExchangeValue >> 32))  // %3
 168     : "memory",
 169       "cc"
 170     );
 171
 172   return CompareValue;
 173 }