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67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
/* See the end of this file for copyright, license, and warranty information. */
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#include <ardix/atom.h>
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void atom_init(atom_t *atom)
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{
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atom->count = 0;
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}
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int atom_get(atom_t *atom)
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{
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int tmp;
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int newval;
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atom_t atom_val;
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__asm__ volatile(
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"1: ldrex %0, [%3] \n" /* atom_val = *atom */
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" add %1, %0, #1 \n" /* newval = atom_val.count + 1 */
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" strex %2, %1, [%3] \n" /* *atom = newval */
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" teq %2, #0 \n" /* store successful? */
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" bne 1b \n" /* -> goto 1 if not */
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" dmb " /* memory barrier */
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: "=&r" (atom_val), "=&r" (newval), "=&r" (tmp)
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: "r" (atom)
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: "cc");
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return newval;
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}
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int atom_put(atom_t *atom)
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{
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int tmp;
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int newval;
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atom_t atom_val;
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__asm__ volatile(
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"1: ldrex %0, [%3] \n" /* atom_val = *atom */
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" sub %1, %0, #1 \n" /* newval = atom_val.count - 1 */
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" strex %2, %1, [%3] \n" /* *atom = newval */
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" teq %2, #0 \n" /* store successful? */
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" bne 1b \n" /* -> goto 1 if not */
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" dmb " /* memory barrier */
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: "=&r" (atom_val), "=&r" (newval), "=&r" (tmp)
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: "r" (atom)
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: "cc");
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return newval;
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}
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int atom_count(atom_t *atom)
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{
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return atom->count;
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}
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/*
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* This file is part of Ardix.
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* Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.
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*
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* Ardix is non-violent software: you may only use, redistribute,
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* and/or modify it under the terms of the CNPLv6+ as found in
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* the LICENSE file in the source code root directory or at
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* <https://git.pixie.town/thufie/CNPL>.
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*
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* Ardix comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPLv6+ for details.
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*/
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