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/* Machine-dependent pthreads configuration and inline functions.
i686 version.
Copyright (C) 1996-2001, 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>.
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; 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 _PT_MACHINE_H
#define _PT_MACHINE_H 1
#ifndef PT_EI
# define PT_EI extern inline __attribute__ ((always_inline))
#endif
#include "kernel-features.h"
#ifndef __ASSEMBLER__
extern long int testandset (int *spinlock);
extern int __compare_and_swap (long int *p, long int oldval, long int newval);
/* 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 __builtin_frame_address (0)
/* Spinlock implementation; required. */
PT_EI long int
testandset (int *spinlock)
{
long int ret;
__asm__ __volatile__ (
"xchgl %0, %1"
: "=r" (ret), "=m" (*spinlock)
: "0" (1), "m" (*spinlock)
: "memory");
return ret;
}
/* Compare-and-swap for semaphores. It's always available on i686. */
#define HAS_COMPARE_AND_SWAP
PT_EI int
__compare_and_swap (long int *p, long int oldval, long int newval)
{
char ret;
long int readval;
__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
: "=q" (ret), "=m" (*p), "=a" (readval)
: "r" (newval), "m" (*p), "a" (oldval)
: "memory");
return ret;
}
#endif
/* If tls.h was included, it will include useldt.h after defining USE_TLS.
We don't want to include it here first when tls.h includes us. */
#if __ASSUME_LDT_WORKS > 0 && !defined _TLS_H
#include "../useldt.h"
#endif
/* The P4 and above really want some help to prevent overheating. */
#define BUSY_WAIT_NOP __asm__ ("rep; nop")
#endif /* pt-machine.h */
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