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- /* Machine-dependent pthreads configuration and inline functions.
- i686 version.
- Copyright (C) 1996-2001, 2002, 2003 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, see <http://www.gnu.org/licenses/>. */
- #ifndef _PT_MACHINE_H
- #define _PT_MACHINE_H 1
- #ifndef PT_EI
- # define PT_EI __extern_always_inline
- #endif
- #include <bits/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 __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")
- #endif /* pt-machine.h */
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