libstdc++-v3/config/cpu/sparc/sparc32/bits/atomicity.h

   1 // Low-level functions for atomic operations: Sparc32 version  -*- C++ -*-
   2
   3 // Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 #ifndef _BITS_ATOMICITY_H
  31 #define _BITS_ATOMICITY_H       1
  32
  33 typedef int _Atomic_word;
  34
  35 static int
  36 __attribute__ ((__unused__))
  37 __exchange_and_add (volatile _Atomic_word* __mem, int __val)
  38 {
  39   static unsigned char __lock;
  40   _Atomic_word __result, __tmp;
  41
  42   __asm__ __volatile__("1:      ldstub  [%1], %0\n\t"
  43                        "        cmp     %0, 0\n\t"
  44                        "        bne     1b\n\t"
  45                        "         nop"
  46                        : "=&r" (__tmp)
  47                        : "r" (&__lock)
  48                        : "memory");
  49   __result = *__mem;
  50   *__mem += __val;
  51   __asm__ __volatile__("stb     %%g0, [%0]"
  52                        : /* no outputs */
  53                        : "r" (&__lock)
  54                        : "memory");
  55   return __result;
  56 }
  57
  58 static void
  59 __attribute__ ((__unused__))
  60 __atomic_add (volatile _Atomic_word* __mem, int __val)
  61 {
  62   static unsigned char __lock;
  63   _Atomic_word __tmp;
  64
  65   __asm__ __volatile__("1:      ldstub  [%1], %0\n\t"
  66                        "        cmp     %0, 0\n\t"
  67                        "        bne     1b\n\t"
  68                        "         nop"
  69                        : "=&r" (__tmp)
  70                        : "r" (&__lock)
  71                        : "memory");
  72   *__mem += __val;
  73   __asm__ __volatile__("stb     %%g0, [%0]"
  74                        : /* no outputs */
  75                        : "r" (&__lock)
  76                        : "memory");
  77 }
  78
  79 #endif /* atomicity.h */