MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c

   1 /** @file
   2   GCC inline implementation of BaseSynchronizationLib processor specific functions.
   3
   4   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5   Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   6   SPDX-License-Identifier: BSD-2-Clause-Patent
   7
   8 **/
   9
  10 /**
  11   Performs an atomic increment of an 32-bit unsigned integer.
  12
  13   Performs an atomic increment of the 32-bit unsigned integer specified by
  14   Value and returns the incremented value. The increment operation must be
  15   performed using MP safe mechanisms.
  16
  17   @param  Value A pointer to the 32-bit value to increment.
  18
  19   @return The incremented value.
  20
  21 **/
  22 UINT32
  23 EFIAPI
  24 InternalSyncIncrement (
  25   IN      volatile UINT32  *Value
  26   )
  27 {
  28   UINT32  Result;
  29
  30   __asm__ __volatile__ (
  31     "movl    $1, %%eax  \n\t"
  32     "lock               \n\t"
  33     "xadd    %%eax, %1  \n\t"
  34     "inc     %%eax      \n\t"
  35     : "=&a" (Result),         // %0
  36       "+m" (*Value)           // %1
  37     :                         // no inputs that aren't also outputs
  38     : "memory",
  39       "cc"
  40   );
  41
  42   return Result;
  43 }
  44
  45 /**
  46   Performs an atomic decrement of an 32-bit unsigned integer.
  47
  48   Performs an atomic decrement of the 32-bit unsigned integer specified by
  49   Value and returns the decremented value. The decrement operation must be
  50   performed using MP safe mechanisms.
  51
  52   @param  Value A pointer to the 32-bit value to decrement.
  53
  54   @return The decremented value.
  55
  56 **/
  57 UINT32
  58 EFIAPI
  59 InternalSyncDecrement (
  60   IN      volatile UINT32  *Value
  61   )
  62 {
  63   UINT32  Result;
  64
  65   __asm__ __volatile__ (
  66     "movl    $-1, %%eax  \n\t"
  67     "lock                \n\t"
  68     "xadd    %%eax, %1   \n\t"
  69     "dec     %%eax       \n\t"
  70     : "=&a" (Result),          // %0
  71       "+m" (*Value)            // %1
  72     :                          // no inputs that aren't also outputs
  73     : "memory",
  74       "cc"
  75   );
  76
  77   return Result;
  78 }
  79
  80 /**
  81   Performs an atomic compare exchange operation on a 16-bit unsigned integer.
  82
  83   Performs an atomic compare exchange operation on the 16-bit unsigned integer
  84   specified by Value.  If Value is equal to CompareValue, then Value is set to
  85   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  86   then Value is returned.  The compare exchange operation must be performed using
  87   MP safe mechanisms.
  88
  89
  90   @param  Value         A pointer to the 16-bit value for the compare exchange
  91                         operation.
  92   @param  CompareValue  16-bit value used in compare operation.
  93   @param  ExchangeValue 16-bit value used in exchange operation.
  94
  95   @return The original *Value before exchange.
  96
  97 **/
  98 UINT16
  99 EFIAPI
 100 InternalSyncCompareExchange16 (
 101   IN OUT volatile  UINT16  *Value,
 102   IN      UINT16           CompareValue,
 103   IN      UINT16           ExchangeValue
 104   )
 105 {
 106   __asm__ __volatile__ (
 107     "lock                 \n\t"
 108     "cmpxchgw    %2, %1   \n\t"
 109     : "+a" (CompareValue),      // %0
 110       "+m" (*Value)             // %1
 111     : "q"  (ExchangeValue)      // %2
 112     : "memory",
 113       "cc"
 114   );
 115
 116   return CompareValue;
 117 }
 118
 119 /**
 120   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 121
 122   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 123   specified by Value.  If Value is equal to CompareValue, then Value is set to
 124   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 125   then Value is returned.  The compare exchange operation must be performed using
 126   MP safe mechanisms.
 127
 128
 129   @param  Value         A pointer to the 32-bit value for the compare exchange
 130                         operation.
 131   @param  CompareValue  32-bit value used in compare operation.
 132   @param  ExchangeValue 32-bit value used in exchange operation.
 133
 134   @return The original *Value before exchange.
 135
 136 **/
 137 UINT32
 138 EFIAPI
 139 InternalSyncCompareExchange32 (
 140   IN OUT volatile  UINT32  *Value,
 141   IN      UINT32           CompareValue,
 142   IN      UINT32           ExchangeValue
 143   )
 144 {
 145   __asm__ __volatile__ (
 146     "lock                 \n\t"
 147     "cmpxchgl    %2, %1   \n\t"
 148     : "+a" (CompareValue),      // %0
 149       "+m" (*Value)             // %1
 150     : "q"  (ExchangeValue)      // %2
 151     : "memory",
 152       "cc"
 153   );
 154
 155   return CompareValue;
 156 }
 157
 158 /**
 159   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 160
 161   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 162   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 163   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 164   The compare exchange operation must be performed using MP safe mechanisms.
 165
 166
 167   @param  Value         A pointer to the 64-bit value for the compare exchange
 168                         operation.
 169   @param  CompareValue  64-bit value used in compare operation.
 170   @param  ExchangeValue 64-bit value used in exchange operation.
 171
 172   @return The original *Value before exchange.
 173
 174 **/
 175 UINT64
 176 EFIAPI
 177 InternalSyncCompareExchange64 (
 178   IN OUT  volatile UINT64  *Value,
 179   IN      UINT64           CompareValue,
 180   IN      UINT64           ExchangeValue
 181   )
 182 {
 183   __asm__ __volatile__ (
 184     "lock                   \n\t"
 185     "cmpxchg8b   (%1)       \n\t"
 186     : "+A"  (CompareValue)                    // %0
 187     : "S"   (Value),                          // %1
 188       "b"   ((UINT32) ExchangeValue),         // %2
 189       "c"   ((UINT32) (ExchangeValue >> 32))  // %3
 190     : "memory",
 191       "cc"
 192   );
 193
 194   return CompareValue;
 195 }