sysdeps/i386/i486/atomicity.h

   1 /* Low-level functions for atomic operations.  ix86 version, x >= 4.
   2    Copyright (C) 1997, 2000, 2001 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _ATOMICITY_H
  21 #define _ATOMICITY_H    1
  22
  23 #include <inttypes.h>
  24
  25
  26 static inline uint32_t
  27 __attribute__ ((unused))
  28 exchange_and_add (volatile uint32_t *mem, uint32_t val)
  29 {
  30   register uint32_t result;
  31   __asm__ __volatile__ ("lock; xaddl %0,%1"
  32                         : "=r" (result), "=m" (*mem) : "0" (val), "1" (*mem));
  33   return result;
  34 }
  35
  36 static inline void
  37 __attribute__ ((unused))
  38 atomic_add (volatile uint32_t *mem, int val)
  39 {
  40   __asm__ __volatile__ ("lock; addl %1,%0"
  41                         : "=m" (*mem) : "ir" (val), "0" (*mem));
  42 }
  43
  44 static inline char
  45 __attribute__ ((unused))
  46 compare_and_swap (volatile long int *p, long int oldval, long int newval)
  47 {
  48   char ret;
  49   long int readval;
  50
  51   __asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
  52                         : "=q" (ret), "=m" (*p), "=a" (readval)
  53                         : "r" (newval), "1" (*p), "a" (oldval));
  54   return ret;
  55 }
  56
  57 #endif /* atomicity.h */