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87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
/* Low-level functions for atomic operations. AM33 version.
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Copyright 1999, 2001 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Alexandre Oliva <aoliva@redhat.com>.
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Based on ../sparc/sparc32/atomicity.h
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _ATOMICITY_H
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#define _ATOMICITY_H 1
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#include <inttypes.h>
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#define __acquire_lock(lock) \
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__asm__ __volatile__("1: bset %1, (%0)\n\t" \
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" beq 1b" \
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: : "a" (&(lock)), "d" (1) \
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: "memory")
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#define __release_lock(lock) lock = 0
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static int
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__attribute__ ((unused))
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exchange_and_add (volatile uint32_t *mem, int val)
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{
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static unsigned char lock;
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int result;
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__acquire_lock (lock);
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result = *mem;
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*mem += val;
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__release_lock (lock);
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return result;
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}
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static void
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__attribute__ ((unused))
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atomic_add (volatile uint32_t *mem, int val)
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{
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static unsigned char lock;
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__acquire_lock (lock);
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*mem += val;
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__release_lock (lock);
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}
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static int
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__attribute__ ((unused))
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compare_and_swap (volatile long int *p, long int oldval, long int newval)
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{
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static unsigned char lock;
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int ret;
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__acquire_lock (lock);
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if (*p != oldval)
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ret = 0;
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else
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{
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*p = newval;
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ret = 1;
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}
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__release_lock (lock);
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return ret;
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}
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#endif /* atomicity.h */
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