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/* Atomic operations. PowerPC version.
Copyright (C) 2003 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#ifndef _BITS_ATOMIC_H
#define _BITS_ATOMIC_H 1
typedef __volatile int __atomic_t;
static inline void
__atomic_inc (__atomic_t *__var)
{
int tmp;
__asm__ ("\n\
0: lwarx %0,0,%1 \n\
add%I2 %0,%0,%2 \n\
stwcx. %0,0,%1 \n\
bne- 0b \n\
" : "=&b"(tmp) : "r" (__var), "Ir"(1) : "cr0", "memory");
}
static inline void
__atomic_dec (__atomic_t *__var)
{
int tmp;
__asm__ ("\n\
0: lwarx %0,0,%1 \n\
add%I2 %0,%0,%2 \n\
stwcx. %0,0,%1 \n\
bne- 0b \n\
" : "=&b"(tmp) : "r" (__var), "Ir"(-1) : "cr0", "memory");
}
static inline int
__atomic_dec_and_test (__atomic_t *__var)
{
unsigned char __ret;
#if 0
__asm__ __volatile ("lock; decl %0; sete %1"
: "=m" (*__var), "=qm" (__ret) : "m" (*__var));
#endif
return __ret != 0;
}
/* We assume that an __atomicptr_t is only used for pointers to
word-aligned objects, and use the lowest bit for a simple lock. */
typedef __volatile int * __atomicptr_t;
/* Actually we don't implement that yet, and assume that we run on
something that has the i486 instruction set. */
static inline int
__atomicptr_compare_and_swap (__atomicptr_t *__ptr, void *__oldval,
void * __newval)
{
int __ret;
__asm__ ("\n\
0: lwarx %0,0,%1 \n\
sub%I2c. %0,%0,%2 \n\
cntlzw %0,%0 \n\
bne- 1f \n\
stwcx. %3,0,%1 \n\
bne- 0b \n\
1: \n\
" : "=&b"(__ret) : "r"(__ptr), "Ir"(__oldval), "r"(__newval) : "cr0", "memory");
return __ret >> 5;
}
#endif
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