MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c

   1 /** @file
   2   GCC inline implementation of BaseSynchronizationLib processor specific functions.
   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
  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 // GCC 4.1 and forward supports atomic builtins
 118 #if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)))
 119
 120   return __sync_val_compare_and_swap (Value, CompareValue, ExchangeValue);
 121
 122 #else
 123
 124   __asm__ __volatile__ (
 125     "                     \n\t"
 126     "lock                 \n\t"
 127     "cmpxchgl    %1, %2   \n\t"
 128     : "=a" (CompareValue)     // %0
 129     : "q"  (ExchangeValue),   // %1
 130       "m"  (*Value),          // %2
 131       "0"  (CompareValue)     // %4
 132     : "memory",
 133       "cc"
 134     );
 135
 136     return CompareValue;
 137
 138 #endif
 139 }
 140
 141 /**
 142   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 143
 144   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 145   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 146   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 147   The compare exchange operation must be performed using MP safe mechanisms.
 148
 149
 150   @param  Value         A pointer to the 64-bit value for the compare exchange
 151                         operation.
 152   @param  CompareValue  64-bit value used in compare operation.
 153   @param  ExchangeValue 64-bit value used in exchange operation.
 154
 155   @return The original *Value before exchange.
 156
 157 **/
 158 UINT64
 159 EFIAPI
 160 InternalSyncCompareExchange64 (
 161   IN OUT  volatile UINT64           *Value,
 162   IN      UINT64                    CompareValue,
 163   IN      UINT64                    ExchangeValue
 164   )
 165 {
 166 // GCC 4.1 and forward supports atomic builtins
 167 #if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)))
 168
 169   return __sync_val_compare_and_swap (Value, CompareValue, ExchangeValue);
 170
 171 #else
 172
 173   __asm__ __volatile__ (
 174     "                       \n\t"
 175     "push        %%ebx      \n\t"
 176     "movl        %2,%%ebx   \n\t"
 177     "lock                   \n\t"
 178     "cmpxchg8b   (%1)       \n\t"
 179     "pop         %%ebx      \n\t"
 180     : "+A"  (CompareValue)                    // %0
 181     : "S"   (Value),                          // %1
 182       "r"   ((UINT32) ExchangeValue),         // %2
 183       "c"   ((UINT32) (ExchangeValue >> 32))  // %3
 184     : "memory",
 185       "cc"
 186     );
 187
 188   return CompareValue;
 189
 190 #endif
 191 }
 192
 193