/* Machine-dependent pthreads configuration and inline functions.   i386 version.   Copyright (C) 1996-2001, 2002 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 __ASSEMBLER__#ifndef PT_EI# define PT_EI extern inline#endifextern 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)/* See if we can optimize for newer cpus... */#if defined __GNUC__ && __GNUC__ >= 2 && defined __i486__ || defined __pentium__ || defined __pentiumpro__/* Spinlock implementation; required.  */PT_EI long inttestandset (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_SWAPPT_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")#else /* Generic i386 implementation *//* Spinlock implementation; required.  */PT_EI long inttestandset (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.   Available on the 486 and above, but not on the 386.   We test dynamically whether it's available or not. */#define HAS_COMPARE_AND_SWAP#define TEST_FOR_COMPARE_AND_SWAPPT_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;}PT_EI intget_eflags (void){  int res;  __asm__ __volatile__ ("pushfl; popl %0" : "=r" (res) : );  return res;}PT_EI voidset_eflags (int newflags){  __asm__ __volatile__ ("pushl %0; popfl" : : "r" (newflags) : "cc");}PT_EI intcompare_and_swap_is_available (void){  int oldflags = get_eflags ();  int changed;  /* Flip AC bit in EFLAGS.  */  set_eflags (oldflags ^ 0x40000);  /* See if bit changed.  */  changed = (get_eflags () ^ oldflags) & 0x40000;  /* Restore EFLAGS.  */  set_eflags (oldflags);  /* If the AC flag did not change, it's a 386 and it lacks cmpxchg.     Otherwise, it's a 486 or above and it has cmpxchg.  */  return changed != 0;}#endif /* Generic i386 implementation */#endif /* __ASSEMBLER__ */#endif /* pt-machine.h */