80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
/* Machine-dependent pthreads configuration and inline functions.
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i686 version.
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Copyright (C) 1996-2001, 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson <rth@tamu.edu>.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#ifndef _PT_MACHINE_H
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#define _PT_MACHINE_H 1
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#ifndef PT_EI
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# define PT_EI extern inline
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#endif
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#include "kernel-features.h"
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#ifndef ASSEMBLER
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extern long int testandset (int *spinlock);
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extern int __compare_and_swap (long int *p, long int oldval, long int newval);
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/* Get some notion of the current stack. Need not be exactly the top
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of the stack, just something somewhere in the current frame. */
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#define CURRENT_STACK_FRAME __builtin_frame_address (0)
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/* Spinlock implementation; required. */
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PT_EI long int
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testandset (int *spinlock)
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{
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long int ret;
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__asm__ __volatile__ (
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"xchgl %0, %1"
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: "=r" (ret), "=m" (*spinlock)
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: "0" (1), "m" (*spinlock)
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: "memory");
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return ret;
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}
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/* Compare-and-swap for semaphores. It's always available on i686. */
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#define HAS_COMPARE_AND_SWAP
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PT_EI int
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__compare_and_swap (long int *p, long int oldval, long int newval)
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{
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char ret;
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long int readval;
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__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
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: "=q" (ret), "=m" (*p), "=a" (readval)
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: "r" (newval), "m" (*p), "a" (oldval)
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: "memory");
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return ret;
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}
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#endif
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#if __ASSUME_LDT_WORKS > 0
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#include "../useldt.h"
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#endif
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/* The P4 and above really want some help to prevent overheating. */
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#define BUSY_WAIT_NOP __asm__ ("rep; nop")
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#endif /* pt-machine.h */
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