MdePkg/Library/BaseSynchronizationLib/X64/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.<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 /**
  20   Performs an atomic increment of an 32-bit unsigned integer.
  21
  22   Performs an atomic increment of the 32-bit unsigned integer specified by
  23   Value and returns the incremented value. The increment operation must be
  24   performed using MP safe mechanisms. The state of the return value is not
  25   guaranteed to be MP safe.
  26
  27   @param  Value A pointer to the 32-bit value to increment.
  28
  29   @return The incremented value.
  30
  31 **/
  32 UINT32
  33 EFIAPI
  34 InternalSyncIncrement (
  35   IN      volatile UINT32    *Value
  36   )
  37 {
  38   UINT32  Result;
  39
  40   __asm__ __volatile__ (
  41     "lock               \n\t"
  42     "incl    %2         \n\t"
  43     "mov     %2, %%eax      "
  44     : "=a" (Result),          // %0
  45       "=m" (*Value)           // %1
  46     : "m"  (*Value)           // %2
  47     : "memory",
  48       "cc"
  49     );
  50
  51   return Result;
  52
  53 }
  54
  55
  56 /**
  57   Performs an atomic decrement of an 32-bit unsigned integer.
  58
  59   Performs an atomic decrement of the 32-bit unsigned integer specified by
  60   Value and returns the decremented value. The decrement 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 decrement.
  65
  66   @return The decremented value.
  67
  68 **/
  69 UINT32
  70 EFIAPI
  71 InternalSyncDecrement (
  72   IN      volatile UINT32       *Value
  73   )
  74 {
  75    UINT32  Result;
  76
  77   __asm__ __volatile__ (
  78     "lock               \n\t"
  79     "decl    %2         \n\t"
  80     "mov     %2, %%eax      "
  81     : "=a" (Result),          // %0
  82       "=m" (*Value)           // %1
  83     : "m"  (*Value)           // %2
  84     : "memory",
  85       "cc"
  86     );
  87
  88   return Result;
  89 }
  90
  91
  92 /**
  93   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  94
  95   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  96   specified by Value.  If Value is equal to CompareValue, then Value is set to
  97   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  98   then Value is returned.  The compare exchange operation must be performed using
  99   MP safe mechanisms.
 100
 101
 102   @param  Value         A pointer to the 32-bit value for the compare exchange
 103                         operation.
 104   @param  CompareValue  32-bit value used in compare operation.
 105   @param  ExchangeValue 32-bit value used in exchange operation.
 106
 107   @return The original *Value before exchange.
 108
 109 **/
 110 UINT32
 111 EFIAPI
 112 InternalSyncCompareExchange32 (
 113   IN OUT volatile  UINT32           *Value,
 114   IN      UINT32                    CompareValue,
 115   IN      UINT32                    ExchangeValue
 116   )
 117 {
 118 // GCC 4.1 and forward supports atomic builtins
 119 #if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)))
 120
 121   return __sync_val_compare_and_swap (Value, CompareValue, ExchangeValue);
 122
 123 #else
 124
 125   __asm__ __volatile__ (
 126     "lock                 \n\t"
 127     "cmpxchgl    %3, %1       "
 128     : "=a" (CompareValue),    // %0
 129       "=m" (*Value)           // %1
 130     : "a"  (CompareValue),    // %2
 131       "r"  (ExchangeValue),   // %3
 132       "m"  (*Value)
 133     : "memory",
 134       "cc"
 135     );
 136
 137     return CompareValue;
 138
 139 #endif
 140 }
 141
 142
 143 /**
 144   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 145
 146   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 147   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 148   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 149   The compare exchange operation must be performed using MP safe mechanisms.
 150
 151
 152   @param  Value         A pointer to the 64-bit value for the compare exchange
 153                         operation.
 154   @param  CompareValue  64-bit value used in compare operation.
 155   @param  ExchangeValue 64-bit value used in exchange operation.
 156
 157   @return The original *Value before exchange.
 158
 159 **/
 160 UINT64
 161 EFIAPI
 162 InternalSyncCompareExchange64 (
 163   IN OUT  volatile UINT64           *Value,
 164   IN      UINT64                    CompareValue,
 165   IN      UINT64                    ExchangeValue
 166   )
 167 {
 168 // GCC 4.1 and forward supports atomic builtins
 169 #if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 1)))
 170
 171   return __sync_val_compare_and_swap (Value, CompareValue, ExchangeValue);
 172
 173 #else
 174
 175   __asm__ __volatile__ (
 176     "lock                 \n\t"
 177     "cmpxchgq    %3, %1       "
 178     : "=a" (CompareValue),    // %0
 179       "=m" (*Value)           // %1
 180     : "a"  (CompareValue),    // %2
 181       "r"  (ExchangeValue),   // %3
 182       "m"  (*Value)
 183     : "memory",
 184       "cc"
 185     );
 186
 187   return CompareValue;
 188
 189 #endif
 190 }
 191
 192