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/* Low-level functions for atomic operations. Sparc32 version.
Copyright (C) 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _ATOMICITY_H
#define _ATOMICITY_H 1
#include <inttypes.h>
static int
__attribute__ ((unused))
exchange_and_add (volatile uint32_t *mem, int val)
{
static unsigned char lock;
int result, tmp;
__asm__ __volatile__("1: ldstub [%1], %0\n\t"
" cmp %0, 0\n\t"
" bne 1b\n\t"
" nop"
: "=&r" (tmp)
: "r" (&lock)
: "memory");
result = *mem;
*mem += val;
__asm__ __volatile__("stb %%g0, [%0]"
: /* no outputs */
: "r" (&lock)
: "memory");
return result;
}
static void
__attribute__ ((unused))
atomic_add (volatile uint32_t *mem, int val)
{
static unsigned char lock;
int tmp;
__asm__ __volatile__("1: ldstub [%1], %0\n\t"
" cmp %0, 0\n\t"
" bne 1b\n\t"
" nop"
: "=&r" (tmp)
: "r" (&lock)
: "memory");
*mem += val;
__asm__ __volatile__("stb %%g0, [%0]"
: /* no outputs */
: "r" (&lock)
: "memory");
}
static int
__attribute__ ((unused))
compare_and_swap (volatile long int *p, long int oldval, long int newval)
{
static unsigned char lock;
int ret, tmp;
__asm__ __volatile__("1: ldstub [%1], %0\n\t"
" cmp %0, 0\n\t"
" bne 1b\n\t"
" nop"
: "=&r" (tmp)
: "r" (&lock)
: "memory");
if (*p != oldval)
ret = 0;
else
{
*p = newval;
ret = 1;
}
__asm__ __volatile__("stb %%g0, [%0]"
: /* no outputs */
: "r" (&lock)
: "memory");
return ret;
}
#endif /* atomicity.h */
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