glibc/linuxthreads/sysdeps/i386/i686/pt-machine.h
Ulrich Drepper 746802f20f Update.
2001-08-29  Ulrich Drepper  <drepper@redhat.com>

	* spinlock.c (__pthread_lock): Top max_count value with
	MAX_ADAPTIVE_SPIN_COUNT.
	* internals.h (MAX_ADAPTIVE_SPIN_COUNT): Define if not already done.

	* sysdeps/i386/i686/pt-machine.h (BUSY_WAIT_NOP): New macro to
	help P4.
2001-08-30 02:13:26 +00:00

70 lines
2.1 KiB
C

/* Machine-dependent pthreads configuration and inline functions.
i686 version.
Copyright (C) 1996, 1997, 1998, 2000, 2001 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 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 PT_EI
# define PT_EI extern inline
#endif
#include "kernel-features.h"
/* 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;
}
#if __ASSUME_LDT_WORKS > 0
#include "../useldt.h"
#endif
/* The P4 and above really want some help to prevent overheating. */
#define BUSY_WAIT_NOP __asm__ ("rep; nop")