157 lines
4.6 KiB
C
157 lines
4.6 KiB
C
/* atomic operations */
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/*
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* Copyright (c) 1997-2015, Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __ATOMIC_H__
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#define __ATOMIC_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef int atomic_t;
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typedef atomic_t atomic_val_t;
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extern atomic_val_t atomic_add(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_and(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_dec(atomic_t *target);
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extern atomic_val_t atomic_inc(atomic_t *target);
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extern atomic_val_t atomic_nand(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_or(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_sub(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_xor(atomic_t *target, atomic_val_t value);
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extern atomic_val_t atomic_clear(atomic_t *target);
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extern atomic_val_t atomic_get(const atomic_t *target);
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extern atomic_val_t atomic_set(atomic_t *target, atomic_val_t value);
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extern int atomic_cas(atomic_t *target,
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atomic_val_t oldValue, atomic_val_t newValue);
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#define ATOMIC_INIT(i) {(i)}
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#define ATOMIC_BITS (sizeof(atomic_val_t) * 8)
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#define ATOMIC_MASK(bit) (1 << ((bit) & (ATOMIC_BITS - 1)))
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#define ATOMIC_ELEM(addr, bit) ((addr) + ((bit) / ATOMIC_BITS))
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/** @brief Test whether a bit is set
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*
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* Test whether bit number bit is set or not.
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*
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* Also works for an array of multiple atomic_t variables, in which
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* case the bit number may go beyond the number of bits in a single
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* atomic_t variable.
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*
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* @param addr base address to start counting from
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* @param bit bit number counted from the base address
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*
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* @return 1 if the bit was set, 0 if it wasn't
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*/
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static inline int atomic_test_bit(const atomic_t *addr, int bit)
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{
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atomic_val_t val = atomic_get(ATOMIC_ELEM(addr, bit));
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return (1 & (val >> (bit & (ATOMIC_BITS - 1))));
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}
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/** @brief Clear a bit and return its old value
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*
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* Atomically clear a bit and return its old value.
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*
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* Also works for an array of multiple atomic_t variables, in which
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* case the bit number may go beyond the number of bits in a single
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* atomic_t variable.
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*
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* @param addr base address to start counting from
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* @param bit bit number counted from the base address
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*
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* @return 1 if the bit was set, 0 if it wasn't
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*/
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static inline int atomic_test_and_clear_bit(atomic_t *addr, int bit)
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{
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atomic_val_t mask = ATOMIC_MASK(bit);
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atomic_val_t old;
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old = atomic_and(ATOMIC_ELEM(addr, bit), ~mask);
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return (old & mask) != 0;
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}
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/** @brief Set a bit and return its old value
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*
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* Atomically set a bit and return its old value.
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*
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* Also works for an array of multiple atomic_t variables, in which
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* case the bit number may go beyond the number of bits in a single
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* atomic_t variable.
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*
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* @param addr base address to start counting from
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* @param bit bit number counted from the base address
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*
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* @return 1 if the bit was set, 0 if it wasn't
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*/
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static inline int atomic_test_and_set_bit(atomic_t *addr, int bit)
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{
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atomic_val_t mask = ATOMIC_MASK(bit);
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atomic_val_t old;
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old = atomic_or(ATOMIC_ELEM(addr, bit), mask);
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return (old & mask) != 0;
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}
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/** @brief Clear a bit
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*
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* Atomically clear a bit.
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*
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* Also works for an array of multiple atomic_t variables, in which
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* case the bit number may go beyond the number of bits in a single
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* atomic_t variable.
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*
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* @param addr base address to start counting from
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* @param bit bit number counted from the base address
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*/
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static inline void atomic_clear_bit(atomic_t *addr, int bit)
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{
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atomic_val_t mask = ATOMIC_MASK(bit);
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atomic_and(ATOMIC_ELEM(addr, bit), ~mask);
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}
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/** @brief Set a bit
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*
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* Atomically set a bit.
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*
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* Also works for an array of multiple atomic_t variables, in which
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* case the bit number may go beyond the number of bits in a single
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* atomic_t variable.
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*
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* @param addr base address to start counting from
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* @param bit bit number counted from the base address
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*/
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static inline void atomic_set_bit(atomic_t *addr, int bit)
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{
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atomic_val_t mask = ATOMIC_MASK(bit);
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atomic_or(ATOMIC_ELEM(addr, bit), mask);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* __ATOMIC_H__ */
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