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80 lines
2.7 KiB
C
80 lines
2.7 KiB
C
4 years ago
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/* SPDX-License-Identifier: BSD-3-Clause */
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/* See the end of this file for copyright, licensing, and warranty information. */
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3 years ago
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#include <ardix/atom.h>
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4 years ago
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3 years ago
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void atom_init(atom_t *atom)
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4 years ago
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{
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3 years ago
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atom->count = 0;
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4 years ago
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}
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4 years ago
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3 years ago
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int atom_get(atom_t *atom)
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4 years ago
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{
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4 years ago
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int tmp;
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int newval;
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3 years ago
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atom_t atom_val;
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4 years ago
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__asm__ volatile(
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3 years ago
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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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4 years ago
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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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3 years ago
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: "=&r" (atom_val), "=&r" (newval), "=&r" (tmp)
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: "r" (atom)
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4 years ago
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: "cc");
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return newval;
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}
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3 years ago
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int atom_put(atom_t *atom)
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4 years ago
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{
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int tmp;
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int newval;
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3 years ago
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atom_t atom_val;
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4 years ago
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__asm__ volatile(
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3 years ago
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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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4 years ago
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: "cc");
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return newval;
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4 years ago
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}
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3 years ago
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int atom_count(atom_t *atom)
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4 years ago
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{
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3 years ago
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return atom->count;
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4 years ago
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}
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/*
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* Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its contributors may be
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* used to endorse or promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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