mirror of
https://github.com/zephyrproject-rtos/zephyr
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f69a38162a
There's a typedef for non-pointer values compatible with atomic non-pointer objects. Add a similar typedef for pointer values, and the corresponding macro for initializing atomic pointer types. This also will simplify replacing the Zephyr atomic API with one based on C11 atomics, should that be desirable. C11 atomic pointer values are not void*. Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
304 lines
7.3 KiB
C
304 lines
7.3 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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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef ZEPHYR_INCLUDE_SYS_ATOMIC_BUILTIN_H_
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#define ZEPHYR_INCLUDE_SYS_ATOMIC_BUILTIN_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Included from <atomic.h> */
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/**
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* @addtogroup atomic_apis Atomic Services APIs
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* @ingroup kernel_apis
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* @{
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*/
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/**
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* @brief Atomic compare-and-set.
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*
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* This routine performs an atomic compare-and-set on @a target. If the current
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* value of @a target equals @a old_value, @a target is set to @a new_value.
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* If the current value of @a target does not equal @a old_value, @a target
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* is left unchanged.
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*
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* @param target Address of atomic variable.
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* @param old_value Original value to compare against.
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* @param new_value New value to store.
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* @return true if @a new_value is written, false otherwise.
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*/
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static inline bool atomic_cas(atomic_t *target, atomic_val_t old_value,
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atomic_val_t new_value)
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{
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return __atomic_compare_exchange_n(target, &old_value, new_value,
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0, __ATOMIC_SEQ_CST,
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__ATOMIC_SEQ_CST);
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}
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/**
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* @brief Atomic compare-and-set with pointer values
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*
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* This routine performs an atomic compare-and-set on @a target. If the current
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* value of @a target equals @a old_value, @a target is set to @a new_value.
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* If the current value of @a target does not equal @a old_value, @a target
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* is left unchanged.
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*
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* @param target Address of atomic variable.
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* @param old_value Original value to compare against.
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* @param new_value New value to store.
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* @return true if @a new_value is written, false otherwise.
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*/
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static inline bool atomic_ptr_cas(atomic_ptr_t *target, atomic_ptr_val_t old_value,
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atomic_ptr_val_t new_value)
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{
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return __atomic_compare_exchange_n(target, &old_value, new_value,
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0, __ATOMIC_SEQ_CST,
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__ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic addition.
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*
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* This routine performs an atomic addition on @a target.
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*
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* @param target Address of atomic variable.
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* @param value Value to add.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_add(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_add(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic subtraction.
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*
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* This routine performs an atomic subtraction on @a target.
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*
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* @param target Address of atomic variable.
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* @param value Value to subtract.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_sub(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_sub(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic increment.
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*
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* This routine performs an atomic increment by 1 on @a target.
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*
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* @param target Address of atomic variable.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_inc(atomic_t *target)
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{
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return atomic_add(target, 1);
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}
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/**
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*
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* @brief Atomic decrement.
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*
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* This routine performs an atomic decrement by 1 on @a target.
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*
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* @param target Address of atomic variable.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_dec(atomic_t *target)
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{
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return atomic_sub(target, 1);
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}
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/**
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*
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* @brief Atomic get.
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*
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* This routine performs an atomic read on @a target.
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*
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* @param target Address of atomic variable.
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*
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* @return Value of @a target.
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*/
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static inline atomic_val_t atomic_get(const atomic_t *target)
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{
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return __atomic_load_n(target, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic get a pointer value
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*
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* This routine performs an atomic read on @a target.
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*
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* @param target Address of pointer variable.
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*
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* @return Value of @a target.
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*/
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static inline atomic_ptr_val_t atomic_ptr_get(const atomic_ptr_t *target)
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{
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return __atomic_load_n(target, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic get-and-set.
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*
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* This routine atomically sets @a target to @a value and returns
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* the previous value of @a target.
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*
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* @param target Address of atomic variable.
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* @param value Value to write to @a target.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_set(atomic_t *target, atomic_val_t value)
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{
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/* This builtin, as described by Intel, is not a traditional
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* test-and-set operation, but rather an atomic exchange operation. It
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* writes value into *ptr, and returns the previous contents of *ptr.
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*/
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return __atomic_exchange_n(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic get-and-set for pointer values
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*
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* This routine atomically sets @a target to @a value and returns
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* the previous value of @a target.
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*
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* @param target Address of atomic variable.
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* @param value Value to write to @a target.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_ptr_val_t atomic_ptr_set(atomic_ptr_t *target, atomic_ptr_val_t value)
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{
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return __atomic_exchange_n(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic clear.
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*
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* This routine atomically sets @a target to zero and returns its previous
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* value. (Hence, it is equivalent to atomic_set(target, 0).)
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*
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* @param target Address of atomic variable.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_clear(atomic_t *target)
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{
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return atomic_set(target, 0);
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}
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/**
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*
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* @brief Atomic clear of a pointer value
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*
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* This routine atomically sets @a target to zero and returns its previous
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* value. (Hence, it is equivalent to atomic_set(target, 0).)
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*
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* @param target Address of atomic variable.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_ptr_val_t atomic_ptr_clear(atomic_ptr_t *target)
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{
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return atomic_ptr_set(target, NULL);
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}
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/**
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*
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* @brief Atomic bitwise inclusive OR.
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*
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* This routine atomically sets @a target to the bitwise inclusive OR of
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* @a target and @a value.
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*
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* @param target Address of atomic variable.
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* @param value Value to OR.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_or(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_or(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic bitwise exclusive OR (XOR).
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*
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* This routine atomically sets @a target to the bitwise exclusive OR (XOR) of
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* @a target and @a value.
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*
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* @param target Address of atomic variable.
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* @param value Value to XOR
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_xor(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_xor(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic bitwise AND.
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*
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* This routine atomically sets @a target to the bitwise AND of @a target
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* and @a value.
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*
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* @param target Address of atomic variable.
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* @param value Value to AND.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_and(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_and(target, value, __ATOMIC_SEQ_CST);
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}
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/**
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*
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* @brief Atomic bitwise NAND.
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*
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* This routine atomically sets @a target to the bitwise NAND of @a target
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* and @a value. (This operation is equivalent to target = ~(target & value).)
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*
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* @param target Address of atomic variable.
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* @param value Value to NAND.
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*
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* @return Previous value of @a target.
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*/
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static inline atomic_val_t atomic_nand(atomic_t *target, atomic_val_t value)
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{
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return __atomic_fetch_nand(target, value, __ATOMIC_SEQ_CST);
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}
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/** @} */
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#ifdef __cplusplus
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}
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#endif
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#endif /* ZEPHYR_INCLUDE_SYS_ATOMIC_BUILTIN_H_ */
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