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/* Machine-dependent pthreads configuration and inline functions.
powerpc version.
Copyright (C) 1996, 1997, 1998 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. */
/* These routines are from Appendix G of the 'PowerPC 601 RISC Microprocessor
User's Manual', by IBM and Motorola. */
/* For multiprocessor systems, we want to ensure all memory accesses
are completed before we reset a lock. */
#if 0
/* on non multiprocessor systems, you can just: */
#define sync() /* nothing */
#else
#define sync() __asm__ __volatile__ ("sync")
#endif
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#define CURRENT_STACK_FRAME stack_pointer
register char * stack_pointer __asm__ ("r1");
/* Compare-and-swap for semaphores. */
/* note that test-and-set(x) is the same as compare-and-swap(x, 0, 1) */
#define HAS_COMPARE_AND_SWAP
#if BROKEN_PPC_ASM_CR0
static
#else
extern inline
#endif
int
__compare_and_swap (long *p, long oldval, long newval)
{
int ret;
sync();
__asm__ __volatile__(
"0: lwarx %0,0,%1 ;"
" xor. %0,%3,%0;"
" bne 1f;"
" stwcx. %2,0,%1;"
" bne- 0b;"
"1: "
: "=&r"(ret)
: "r"(p), "r"(newval), "r"(oldval)
: "cr0", "memory");
sync();
return ret == 0;
}
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