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| ganlikun |
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/** \addtogroup platform */
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/** @{*/
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/*
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* Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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| ganlikun |
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* 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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| ganlikun |
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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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| ganlikun |
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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| ganlikun |
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* 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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| ganlikun |
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*/
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#ifndef __MBED_UTIL_CRITICAL_H__
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#define __MBED_UTIL_CRITICAL_H__
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** Determine the current interrupts enabled state
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| ganlikun |
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*
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| ganlikun |
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* This function can be called to determine whether or not interrupts are currently enabled.
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| ganlikun |
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* @note
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| ganlikun |
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* NOTE:
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| ganlikun |
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* This function works for both cortex-A and cortex-M, although the underlyng implementation
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| ganlikun |
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* differs.
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| ganlikun |
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* @return true if interrupts are enabled, false otherwise
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*/
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| ganlikun |
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bool core_util_are_interrupts_enabled(void);
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| ganlikun |
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/** Determine if this code is executing from an interrupt
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| ganlikun |
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*
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| ganlikun |
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* This function can be called to determine if the code is running on interrupt context.
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| ganlikun |
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* @note
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| ganlikun |
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* NOTE:
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| ganlikun |
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* This function works for both cortex-A and cortex-M, although the underlyng implementation
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| ganlikun |
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* differs.
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| ganlikun |
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* @return true if in an isr, false otherwise
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| ganlikun |
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*/
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| ganlikun |
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bool core_util_is_isr_active(void);
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| ganlikun |
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| ganlikun |
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/** Mark the start of a critical section
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*
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* This function should be called to mark the start of a critical section of code.
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| ganlikun |
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* @note
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* NOTES:
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* 1) The use of this style of critical section is targetted at C based implementations.
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* 2) These critical sections can be nested.
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* 3) The interrupt enable state on entry to the first critical section (of a nested set, or single
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| ganlikun |
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* section) will be preserved on exit from the section.
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| ganlikun |
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* 4) This implementation will currently only work on code running in privileged mode.
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| ganlikun |
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*/
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| ganlikun |
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void core_util_critical_section_enter(void);
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| ganlikun |
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| ganlikun |
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/** Mark the end of a critical section
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*
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| ganlikun |
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* This function should be called to mark the end of a critical section of code.
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| ganlikun |
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* @note
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| ganlikun |
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* NOTES:
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| ganlikun |
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* 1) The use of this style of critical section is targetted at C based implementations.
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| ganlikun |
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* 2) These critical sections can be nested.
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| ganlikun |
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* 3) The interrupt enable state on entry to the first critical section (of a nested set, or single
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| ganlikun |
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* section) will be preserved on exit from the section.
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| ganlikun |
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* 4) This implementation will currently only work on code running in privileged mode.
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| ganlikun |
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*/
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| ganlikun |
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void core_util_critical_section_exit(void);
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/**
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* Atomic compare and set. It compares the contents of a memory location to a
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| ganlikun |
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* given value and, only if they are the same, modifies the contents of that
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| ganlikun |
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* memory location to a given new value. This is done as a single atomic
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| ganlikun |
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* operation. The atomicity guarantees that the new value is calculated based on
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| ganlikun |
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* up-to-date information; if the value had been updated by another thread in
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| ganlikun |
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* the meantime, the write would fail due to a mismatched expectedCurrentValue.
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| ganlikun |
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*
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| ganlikun |
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* Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
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| ganlikun |
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* you to the article on compare-and swap].
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| ganlikun |
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*
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| ganlikun |
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* @param ptr The target memory location.
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| ganlikun |
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* @param[in,out] expectedCurrentValue A pointer to some location holding the
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| ganlikun |
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* expected current value of the data being set atomically.
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| ganlikun |
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* The computed 'desiredValue' should be a function of this current value.
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| ganlikun |
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* @note: This is an in-out parameter. In the
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| ganlikun |
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* failure case of atomic_cas (where the
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| ganlikun |
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* destination isn't set), the pointee of expectedCurrentValue is
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* updated with the current value.
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* @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
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*
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* @return true if the memory location was atomically
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* updated with the desired value (after verifying
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| ganlikun |
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* that it contained the expectedCurrentValue),
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* false otherwise. In the failure case,
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* exepctedCurrentValue is updated with the new
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| ganlikun |
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* value of the target memory location.
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*
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* pseudocode:
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| ganlikun |
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* function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
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| ganlikun |
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* if *p != *old {
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* *old = *p
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* return false
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* }
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* *p = new
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* return true
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* }
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| ganlikun |
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*
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* @note: In the failure case (where the destination isn't set), the value
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| ganlikun |
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* pointed to by expectedCurrentValue is still updated with the current value.
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| ganlikun |
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* This property helps writing concise code for the following incr:
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| ganlikun |
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*
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* function incr(p : pointer to int, a : int) returns int {
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* done = false
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* value = *p // This fetch operation need not be atomic.
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* while not done {
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| ganlikun |
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* done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
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* }
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* return value + a
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| ganlikun |
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* }
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| ganlikun |
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*/
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| ganlikun |
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bool core_util_atomic_cas_u8(uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue);
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| ganlikun |
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| ganlikun |
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/**
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| ganlikun |
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* Atomic compare and set. It compares the contents of a memory location to a
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| ganlikun |
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136
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* given value and, only if they are the same, modifies the contents of that
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| ganlikun |
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* memory location to a given new value. This is done as a single atomic
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| ganlikun |
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138
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* operation. The atomicity guarantees that the new value is calculated based on
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| ganlikun |
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* up-to-date information; if the value had been updated by another thread in
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| ganlikun |
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* the meantime, the write would fail due to a mismatched expectedCurrentValue.
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| ganlikun |
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*
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| ganlikun |
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* Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
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| ganlikun |
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|
143
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* you to the article on compare-and swap].
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| ganlikun |
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144
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*
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| ganlikun |
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* @param ptr The target memory location.
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| ganlikun |
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* @param[in,out] expectedCurrentValue A pointer to some location holding the
|
| ganlikun |
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147
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* expected current value of the data being set atomically.
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| ganlikun |
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148
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* The computed 'desiredValue' should be a function of this current value.
|
| ganlikun |
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149
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* @note: This is an in-out parameter. In the
|
| ganlikun |
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|
150
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* failure case of atomic_cas (where the
|
| ganlikun |
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|
151
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* destination isn't set), the pointee of expectedCurrentValue is
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| ganlikun |
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152
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* updated with the current value.
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| ganlikun |
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153
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* @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
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| ganlikun |
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154
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*
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| ganlikun |
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* @return true if the memory location was atomically
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| ganlikun |
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|
156
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* updated with the desired value (after verifying
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| ganlikun |
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|
157
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* that it contained the expectedCurrentValue),
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| ganlikun |
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|
158
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* false otherwise. In the failure case,
|
| ganlikun |
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|
159
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* exepctedCurrentValue is updated with the new
|
| ganlikun |
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160
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* value of the target memory location.
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| ganlikun |
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|
161
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*
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| ganlikun |
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|
162
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* pseudocode:
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| ganlikun |
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163
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* function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
|
| ganlikun |
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164
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* if *p != *old {
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| ganlikun |
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* *old = *p
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| ganlikun |
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* return false
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| ganlikun |
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* }
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| ganlikun |
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* *p = new
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| ganlikun |
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* return true
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| ganlikun |
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170
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* }
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| ganlikun |
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|
171
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*
|
| ganlikun |
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* @note: In the failure case (where the destination isn't set), the value
|
| ganlikun |
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|
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* pointed to by expectedCurrentValue is still updated with the current value.
|
| ganlikun |
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|
174
|
* This property helps writing concise code for the following incr:
|
| ganlikun |
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|
175
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*
|
| ganlikun |
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* function incr(p : pointer to int, a : int) returns int {
|
| ganlikun |
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|
177
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* done = false
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| ganlikun |
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|
178
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* value = *p // This fetch operation need not be atomic.
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| ganlikun |
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|
179
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* while not done {
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| ganlikun |
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180
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* done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
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| ganlikun |
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* }
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| ganlikun |
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* return value + a
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| ganlikun |
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|
183
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* }
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| ganlikun |
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184
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*/
|
| ganlikun |
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185
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bool core_util_atomic_cas_u16(uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue);
|
| ganlikun |
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|
186
|
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| ganlikun |
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|
187
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/**
|
| ganlikun |
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|
188
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* Atomic compare and set. It compares the contents of a memory location to a
|
| ganlikun |
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|
189
|
* given value and, only if they are the same, modifies the contents of that
|
| ganlikun |
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|
190
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* memory location to a given new value. This is done as a single atomic
|
| ganlikun |
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|
191
|
* operation. The atomicity guarantees that the new value is calculated based on
|
| ganlikun |
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|
192
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* up-to-date information; if the value had been updated by another thread in
|
| ganlikun |
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|
193
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* the meantime, the write would fail due to a mismatched expectedCurrentValue.
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| ganlikun |
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|
194
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*
|
| ganlikun |
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|
195
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* Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
|
| ganlikun |
0:06036f8bee2d
|
196
|
* you to the article on compare-and swap].
|
| ganlikun |
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|
197
|
*
|
| ganlikun |
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198
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* @param ptr The target memory location.
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* @param[in,out] expectedCurrentValue A pointer to some location holding the
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* expected current value of the data being set atomically.
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* The computed 'desiredValue' should be a function of this current value.
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* @note: This is an in-out parameter. In the
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* failure case of atomic_cas (where the
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* destination isn't set), the pointee of expectedCurrentValue is
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* updated with the current value.
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* @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
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*
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* @return true if the memory location was atomically
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* updated with the desired value (after verifying
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* that it contained the expectedCurrentValue),
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* false otherwise. In the failure case,
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* exepctedCurrentValue is updated with the new
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* value of the target memory location.
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*
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* pseudocode:
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* function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
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* if *p != *old {
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* *old = *p
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* return false
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* }
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* *p = new
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* return true
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* }
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*
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* @note: In the failure case (where the destination isn't set), the value
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* pointed to by expectedCurrentValue is still updated with the current value.
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* This property helps writing concise code for the following incr:
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*
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* function incr(p : pointer to int, a : int) returns int {
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* done = false
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* value = *p // This fetch operation need not be atomic.
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* while not done {
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* done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
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* }
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* return value + a
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* }
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*/
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bool core_util_atomic_cas_u32(uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue);
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/**
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* Atomic compare and set. It compares the contents of a memory location to a
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* given value and, only if they are the same, modifies the contents of that
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* memory location to a given new value. This is done as a single atomic
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* operation. The atomicity guarantees that the new value is calculated based on
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* up-to-date information; if the value had been updated by another thread in
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* the meantime, the write would fail due to a mismatched expectedCurrentValue.
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*
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* Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
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* you to the article on compare-and swap].
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*
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* @param ptr The target memory location.
|
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|
* @param[in,out] expectedCurrentValue A pointer to some location holding the
|
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253
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* expected current value of the data being set atomically.
|
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|
* The computed 'desiredValue' should be a function of this current value.
|
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|
* @note: This is an in-out parameter. In the
|
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|
256
|
* failure case of atomic_cas (where the
|
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|
* destination isn't set), the pointee of expectedCurrentValue is
|
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|
* updated with the current value.
|
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|
* @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
|
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|
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|
*
|
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|
* @return true if the memory location was atomically
|
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|
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|
* updated with the desired value (after verifying
|
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|
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|
* that it contained the expectedCurrentValue),
|
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|
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|
* false otherwise. In the failure case,
|
| ganlikun |
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|
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|
* exepctedCurrentValue is updated with the new
|
| ganlikun |
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266
|
* value of the target memory location.
|
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|
267
|
*
|
| ganlikun |
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|
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|
* pseudocode:
|
| ganlikun |
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|
269
|
* function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
|
| ganlikun |
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|
270
|
* if *p != *old {
|
| ganlikun |
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|
271
|
* *old = *p
|
| ganlikun |
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|
272
|
* return false
|
| ganlikun |
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|
273
|
* }
|
| ganlikun |
0:06036f8bee2d
|
274
|
* *p = new
|
| ganlikun |
0:06036f8bee2d
|
275
|
* return true
|
| ganlikun |
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|
276
|
* }
|
| ganlikun |
0:06036f8bee2d
|
277
|
*
|
| ganlikun |
0:06036f8bee2d
|
278
|
* @note: In the failure case (where the destination isn't set), the value
|
| ganlikun |
0:06036f8bee2d
|
279
|
* pointed to by expectedCurrentValue is still updated with the current value.
|
| ganlikun |
0:06036f8bee2d
|
280
|
* This property helps writing concise code for the following incr:
|
| ganlikun |
0:06036f8bee2d
|
281
|
*
|
| ganlikun |
0:06036f8bee2d
|
282
|
* function incr(p : pointer to int, a : int) returns int {
|
| ganlikun |
0:06036f8bee2d
|
283
|
* done = false
|
| ganlikun |
0:06036f8bee2d
|
284
|
* value = *p // This fetch operation need not be atomic.
|
| ganlikun |
0:06036f8bee2d
|
285
|
* while not done {
|
| ganlikun |
0:06036f8bee2d
|
286
|
* done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
|
| ganlikun |
0:06036f8bee2d
|
287
|
* }
|
| ganlikun |
0:06036f8bee2d
|
288
|
* return value + a
|
| ganlikun |
0:06036f8bee2d
|
289
|
* }
|
| ganlikun |
0:06036f8bee2d
|
290
|
*/
|
| ganlikun |
0:06036f8bee2d
|
291
|
bool core_util_atomic_cas_ptr(void **ptr, void **expectedCurrentValue, void *desiredValue);
|
| ganlikun |
0:06036f8bee2d
|
292
|
|
| ganlikun |
0:06036f8bee2d
|
293
|
/**
|
| ganlikun |
0:06036f8bee2d
|
294
|
* Atomic increment.
|
| ganlikun |
0:06036f8bee2d
|
295
|
* @param valuePtr Target memory location being incremented.
|
| ganlikun |
0:06036f8bee2d
|
296
|
* @param delta The amount being incremented.
|
| ganlikun |
0:06036f8bee2d
|
297
|
* @return The new incremented value.
|
| ganlikun |
0:06036f8bee2d
|
298
|
*/
|
| ganlikun |
0:06036f8bee2d
|
299
|
uint8_t core_util_atomic_incr_u8(uint8_t *valuePtr, uint8_t delta);
|
| ganlikun |
0:06036f8bee2d
|
300
|
|
| ganlikun |
0:06036f8bee2d
|
301
|
/**
|
| ganlikun |
0:06036f8bee2d
|
302
|
* Atomic increment.
|
| ganlikun |
0:06036f8bee2d
|
303
|
* @param valuePtr Target memory location being incremented.
|
| ganlikun |
0:06036f8bee2d
|
304
|
* @param delta The amount being incremented.
|
| ganlikun |
0:06036f8bee2d
|
305
|
* @return The new incremented value.
|
| ganlikun |
0:06036f8bee2d
|
306
|
*/
|
| ganlikun |
0:06036f8bee2d
|
307
|
uint16_t core_util_atomic_incr_u16(uint16_t *valuePtr, uint16_t delta);
|
| ganlikun |
0:06036f8bee2d
|
308
|
|
| ganlikun |
0:06036f8bee2d
|
309
|
/**
|
| ganlikun |
0:06036f8bee2d
|
310
|
* Atomic increment.
|
| ganlikun |
0:06036f8bee2d
|
311
|
* @param valuePtr Target memory location being incremented.
|
| ganlikun |
0:06036f8bee2d
|
312
|
* @param delta The amount being incremented.
|
| ganlikun |
0:06036f8bee2d
|
313
|
* @return The new incremented value.
|
| ganlikun |
0:06036f8bee2d
|
314
|
*/
|
| ganlikun |
0:06036f8bee2d
|
315
|
uint32_t core_util_atomic_incr_u32(uint32_t *valuePtr, uint32_t delta);
|
| ganlikun |
0:06036f8bee2d
|
316
|
|
| ganlikun |
0:06036f8bee2d
|
317
|
/**
|
| ganlikun |
0:06036f8bee2d
|
318
|
* Atomic increment.
|
| ganlikun |
0:06036f8bee2d
|
319
|
* @param valuePtr Target memory location being incremented.
|
| ganlikun |
0:06036f8bee2d
|
320
|
* @param delta The amount being incremented in bytes.
|
| ganlikun |
0:06036f8bee2d
|
321
|
* @return The new incremented value.
|
| ganlikun |
0:06036f8bee2d
|
322
|
*
|
| ganlikun |
0:06036f8bee2d
|
323
|
* @note The type of the pointer argument is not taken into account
|
| ganlikun |
0:06036f8bee2d
|
324
|
* and the pointer is incremented by bytes.
|
| ganlikun |
0:06036f8bee2d
|
325
|
*/
|
| ganlikun |
0:06036f8bee2d
|
326
|
void *core_util_atomic_incr_ptr(void **valuePtr, ptrdiff_t delta);
|
| ganlikun |
0:06036f8bee2d
|
327
|
|
| ganlikun |
0:06036f8bee2d
|
328
|
/**
|
| ganlikun |
0:06036f8bee2d
|
329
|
* Atomic decrement.
|
| ganlikun |
0:06036f8bee2d
|
330
|
* @param valuePtr Target memory location being decremented.
|
| ganlikun |
0:06036f8bee2d
|
331
|
* @param delta The amount being decremented.
|
| ganlikun |
0:06036f8bee2d
|
332
|
* @return The new decremented value.
|
| ganlikun |
0:06036f8bee2d
|
333
|
*/
|
| ganlikun |
0:06036f8bee2d
|
334
|
uint8_t core_util_atomic_decr_u8(uint8_t *valuePtr, uint8_t delta);
|
| ganlikun |
0:06036f8bee2d
|
335
|
|
| ganlikun |
0:06036f8bee2d
|
336
|
/**
|
| ganlikun |
0:06036f8bee2d
|
337
|
* Atomic decrement.
|
| ganlikun |
0:06036f8bee2d
|
338
|
* @param valuePtr Target memory location being decremented.
|
| ganlikun |
0:06036f8bee2d
|
339
|
* @param delta The amount being decremented.
|
| ganlikun |
0:06036f8bee2d
|
340
|
* @return The new decremented value.
|
| ganlikun |
0:06036f8bee2d
|
341
|
*/
|
| ganlikun |
0:06036f8bee2d
|
342
|
uint16_t core_util_atomic_decr_u16(uint16_t *valuePtr, uint16_t delta);
|
| ganlikun |
0:06036f8bee2d
|
343
|
|
| ganlikun |
0:06036f8bee2d
|
344
|
/**
|
| ganlikun |
0:06036f8bee2d
|
345
|
* Atomic decrement.
|
| ganlikun |
0:06036f8bee2d
|
346
|
* @param valuePtr Target memory location being decremented.
|
| ganlikun |
0:06036f8bee2d
|
347
|
* @param delta The amount being decremented.
|
| ganlikun |
0:06036f8bee2d
|
348
|
* @return The new decremented value.
|
| ganlikun |
0:06036f8bee2d
|
349
|
*/
|
| ganlikun |
0:06036f8bee2d
|
350
|
uint32_t core_util_atomic_decr_u32(uint32_t *valuePtr, uint32_t delta);
|
| ganlikun |
0:06036f8bee2d
|
351
|
|
| ganlikun |
0:06036f8bee2d
|
352
|
/**
|
| ganlikun |
0:06036f8bee2d
|
353
|
* Atomic decrement.
|
| ganlikun |
0:06036f8bee2d
|
354
|
* @param valuePtr Target memory location being decremented.
|
| ganlikun |
0:06036f8bee2d
|
355
|
* @param delta The amount being decremented in bytes.
|
| ganlikun |
0:06036f8bee2d
|
356
|
* @return The new decremented value.
|
| ganlikun |
0:06036f8bee2d
|
357
|
*
|
| ganlikun |
0:06036f8bee2d
|
358
|
* @note The type of the pointer argument is not taken into account
|
| ganlikun |
0:06036f8bee2d
|
359
|
* and the pointer is decremented by bytes
|
| ganlikun |
0:06036f8bee2d
|
360
|
*/
|
| ganlikun |
0:06036f8bee2d
|
361
|
void *core_util_atomic_decr_ptr(void **valuePtr, ptrdiff_t delta);
|
| ganlikun |
0:06036f8bee2d
|
362
|
|
| ganlikun |
0:06036f8bee2d
|
363
|
#ifdef __cplusplus
|
| ganlikun |
0:06036f8bee2d
|
364
|
} // extern "C"
|
| ganlikun |
0:06036f8bee2d
|
365
|
#endif
|
| ganlikun |
0:06036f8bee2d
|
366
|
|
| ganlikun |
0:06036f8bee2d
|
367
|
|
| ganlikun |
0:06036f8bee2d
|
368
|
#endif // __MBED_UTIL_CRITICAL_H__
|
| ganlikun |
0:06036f8bee2d
|
369
|
|
| ganlikun |
0:06036f8bee2d
|
370
|
/** @}*/
|
| ganlikun |
0:06036f8bee2d
|
371
|
|