Руслан Бредун / Mbed 2 deprecated stm32-sensor-base2

test

Dependencies:   mbed Watchdog

Dependents:   STM32-MC_node

mbed/platform/mbed_critical.h@0:d383e2dee0f7, 2020-07-06 (annotated)

Committer:
ommpy
Date:
Mon Jul 06 17:18:59 2020 +0530
Revision:
0:d383e2dee0f7
first commit

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ommpy 0:d383e2dee0f7 1
ommpy 0:d383e2dee0f7 2 /*
ommpy 0:d383e2dee0f7 3 * Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
ommpy 0:d383e2dee0f7 4 * SPDX-License-Identifier: Apache-2.0
ommpy 0:d383e2dee0f7 5 *
ommpy 0:d383e2dee0f7 6 * Licensed under the Apache License, Version 2.0 (the "License"); you may
ommpy 0:d383e2dee0f7 7 * not use this file except in compliance with the License.
ommpy 0:d383e2dee0f7 8 * You may obtain a copy of the License at
ommpy 0:d383e2dee0f7 9 *
ommpy 0:d383e2dee0f7 10 * http://www.apache.org/licenses/LICENSE-2.0
ommpy 0:d383e2dee0f7 11 *
ommpy 0:d383e2dee0f7 12 * Unless required by applicable law or agreed to in writing, software
ommpy 0:d383e2dee0f7 13 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
ommpy 0:d383e2dee0f7 14 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ommpy 0:d383e2dee0f7 15 * See the License for the specific language governing permissions and
ommpy 0:d383e2dee0f7 16 * limitations under the License.
ommpy 0:d383e2dee0f7 17 */
ommpy 0:d383e2dee0f7 18
ommpy 0:d383e2dee0f7 19 #ifndef __MBED_UTIL_CRITICAL_H__
ommpy 0:d383e2dee0f7 20 #define __MBED_UTIL_CRITICAL_H__
ommpy 0:d383e2dee0f7 21
ommpy 0:d383e2dee0f7 22 #include <stdbool.h>
ommpy 0:d383e2dee0f7 23 #include <stdint.h>
ommpy 0:d383e2dee0f7 24 #include <stddef.h>
ommpy 0:d383e2dee0f7 25
ommpy 0:d383e2dee0f7 26 #ifdef __cplusplus
ommpy 0:d383e2dee0f7 27 extern "C" {
ommpy 0:d383e2dee0f7 28 #endif
ommpy 0:d383e2dee0f7 29
ommpy 0:d383e2dee0f7 30 /** \addtogroup platform */
ommpy 0:d383e2dee0f7 31 /** @{*/
ommpy 0:d383e2dee0f7 32 /**
ommpy 0:d383e2dee0f7 33 * \defgroup platform_critical critical section function
ommpy 0:d383e2dee0f7 34 * @{
ommpy 0:d383e2dee0f7 35 */
ommpy 0:d383e2dee0f7 36
ommpy 0:d383e2dee0f7 37 /** Determine the current interrupts enabled state
ommpy 0:d383e2dee0f7 38 *
ommpy 0:d383e2dee0f7 39 * This function can be called to determine whether or not interrupts are currently enabled.
ommpy 0:d383e2dee0f7 40 * @note
ommpy 0:d383e2dee0f7 41 * NOTE:
ommpy 0:d383e2dee0f7 42 * This function works for both cortex-A and cortex-M, although the underlying implementation
ommpy 0:d383e2dee0f7 43 * differs.
ommpy 0:d383e2dee0f7 44 * @return true if interrupts are enabled, false otherwise
ommpy 0:d383e2dee0f7 45 */
ommpy 0:d383e2dee0f7 46 bool core_util_are_interrupts_enabled(void);
ommpy 0:d383e2dee0f7 47
ommpy 0:d383e2dee0f7 48 /** Determine if this code is executing from an interrupt
ommpy 0:d383e2dee0f7 49 *
ommpy 0:d383e2dee0f7 50 * This function can be called to determine if the code is running on interrupt context.
ommpy 0:d383e2dee0f7 51 * @note
ommpy 0:d383e2dee0f7 52 * NOTE:
ommpy 0:d383e2dee0f7 53 * This function works for both cortex-A and cortex-M, although the underlying implementation
ommpy 0:d383e2dee0f7 54 * differs.
ommpy 0:d383e2dee0f7 55 * @return true if in an isr, false otherwise
ommpy 0:d383e2dee0f7 56 */
ommpy 0:d383e2dee0f7 57 bool core_util_is_isr_active(void);
ommpy 0:d383e2dee0f7 58
ommpy 0:d383e2dee0f7 59 /** Mark the start of a critical section
ommpy 0:d383e2dee0f7 60 *
ommpy 0:d383e2dee0f7 61 * This function should be called to mark the start of a critical section of code.
ommpy 0:d383e2dee0f7 62 * @note
ommpy 0:d383e2dee0f7 63 * NOTES:
ommpy 0:d383e2dee0f7 64 * 1) The use of this style of critical section is targetted at C based implementations.
ommpy 0:d383e2dee0f7 65 * 2) These critical sections can be nested.
ommpy 0:d383e2dee0f7 66 * 3) The interrupt enable state on entry to the first critical section (of a nested set, or single
ommpy 0:d383e2dee0f7 67 * section) will be preserved on exit from the section.
ommpy 0:d383e2dee0f7 68 * 4) This implementation will currently only work on code running in privileged mode.
ommpy 0:d383e2dee0f7 69 */
ommpy 0:d383e2dee0f7 70 void core_util_critical_section_enter(void);
ommpy 0:d383e2dee0f7 71
ommpy 0:d383e2dee0f7 72 /** Mark the end of a critical section
ommpy 0:d383e2dee0f7 73 *
ommpy 0:d383e2dee0f7 74 * This function should be called to mark the end of a critical section of code.
ommpy 0:d383e2dee0f7 75 * @note
ommpy 0:d383e2dee0f7 76 * NOTES:
ommpy 0:d383e2dee0f7 77 * 1) The use of this style of critical section is targetted at C based implementations.
ommpy 0:d383e2dee0f7 78 * 2) These critical sections can be nested.
ommpy 0:d383e2dee0f7 79 * 3) The interrupt enable state on entry to the first critical section (of a nested set, or single
ommpy 0:d383e2dee0f7 80 * section) will be preserved on exit from the section.
ommpy 0:d383e2dee0f7 81 * 4) This implementation will currently only work on code running in privileged mode.
ommpy 0:d383e2dee0f7 82 */
ommpy 0:d383e2dee0f7 83 void core_util_critical_section_exit(void);
ommpy 0:d383e2dee0f7 84
ommpy 0:d383e2dee0f7 85 /**
ommpy 0:d383e2dee0f7 86 * Determine if we are currently in a critical section
ommpy 0:d383e2dee0f7 87 *
ommpy 0:d383e2dee0f7 88 * @return true if in a critical section, false otherwise.
ommpy 0:d383e2dee0f7 89 */
ommpy 0:d383e2dee0f7 90 bool core_util_in_critical_section(void);
ommpy 0:d383e2dee0f7 91
ommpy 0:d383e2dee0f7 92 /**
ommpy 0:d383e2dee0f7 93 * A lock-free, primitive atomic flag.
ommpy 0:d383e2dee0f7 94 *
ommpy 0:d383e2dee0f7 95 * Emulate C11's atomic_flag. The flag is initially in an indeterminate state
ommpy 0:d383e2dee0f7 96 * unless explicitly initialized with CORE_UTIL_ATOMIC_FLAG_INIT.
ommpy 0:d383e2dee0f7 97 */
ommpy 0:d383e2dee0f7 98 typedef struct core_util_atomic_flag {
ommpy 0:d383e2dee0f7 99 uint8_t _flag;
ommpy 0:d383e2dee0f7 100 } core_util_atomic_flag;
ommpy 0:d383e2dee0f7 101
ommpy 0:d383e2dee0f7 102 /**
ommpy 0:d383e2dee0f7 103 * Initializer for a core_util_atomic_flag.
ommpy 0:d383e2dee0f7 104 *
ommpy 0:d383e2dee0f7 105 * Example:
ommpy 0:d383e2dee0f7 106 * ~~~
ommpy 0:d383e2dee0f7 107 * core_util_atomic_flag in_progress = CORE_UTIL_ATOMIC_FLAG_INIT;
ommpy 0:d383e2dee0f7 108 * ~~~
ommpy 0:d383e2dee0f7 109 */
ommpy 0:d383e2dee0f7 110 #define CORE_UTIL_ATOMIC_FLAG_INIT { 0 }
ommpy 0:d383e2dee0f7 111
ommpy 0:d383e2dee0f7 112 /**
ommpy 0:d383e2dee0f7 113 * Atomic test and set.
ommpy 0:d383e2dee0f7 114 *
ommpy 0:d383e2dee0f7 115 * Atomically tests then sets the flag to true, returning the previous value.
ommpy 0:d383e2dee0f7 116 *
ommpy 0:d383e2dee0f7 117 * @param flagPtr Target flag being tested and set.
ommpy 0:d383e2dee0f7 118 * @return The previous value.
ommpy 0:d383e2dee0f7 119 */
ommpy 0:d383e2dee0f7 120 bool core_util_atomic_flag_test_and_set(volatile core_util_atomic_flag *flagPtr);
ommpy 0:d383e2dee0f7 121
ommpy 0:d383e2dee0f7 122 /**
ommpy 0:d383e2dee0f7 123 * Atomic clear.
ommpy 0:d383e2dee0f7 124 *
ommpy 0:d383e2dee0f7 125 * @param flagPtr Target flag being cleared.
ommpy 0:d383e2dee0f7 126 */
ommpy 0:d383e2dee0f7 127 void core_util_atomic_flag_clear(volatile core_util_atomic_flag *flagPtr);
ommpy 0:d383e2dee0f7 128
ommpy 0:d383e2dee0f7 129 /**
ommpy 0:d383e2dee0f7 130 * Atomic compare and set. It compares the contents of a memory location to a
ommpy 0:d383e2dee0f7 131 * given value and, only if they are the same, modifies the contents of that
ommpy 0:d383e2dee0f7 132 * memory location to a given new value. This is done as a single atomic
ommpy 0:d383e2dee0f7 133 * operation. The atomicity guarantees that the new value is calculated based on
ommpy 0:d383e2dee0f7 134 * up-to-date information; if the value had been updated by another thread in
ommpy 0:d383e2dee0f7 135 * the meantime, the write would fail due to a mismatched expectedCurrentValue.
ommpy 0:d383e2dee0f7 136 *
ommpy 0:d383e2dee0f7 137 * Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
ommpy 0:d383e2dee0f7 138 * you to the article on compare-and swap].
ommpy 0:d383e2dee0f7 139 *
ommpy 0:d383e2dee0f7 140 * @param ptr The target memory location.
ommpy 0:d383e2dee0f7 141 * @param[in,out] expectedCurrentValue A pointer to some location holding the
ommpy 0:d383e2dee0f7 142 * expected current value of the data being set atomically.
ommpy 0:d383e2dee0f7 143 * The computed 'desiredValue' should be a function of this current value.
ommpy 0:d383e2dee0f7 144 * @note: This is an in-out parameter. In the
ommpy 0:d383e2dee0f7 145 * failure case of atomic_cas (where the
ommpy 0:d383e2dee0f7 146 * destination isn't set), the pointee of expectedCurrentValue is
ommpy 0:d383e2dee0f7 147 * updated with the current value.
ommpy 0:d383e2dee0f7 148 * @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
ommpy 0:d383e2dee0f7 149 *
ommpy 0:d383e2dee0f7 150 * @return true if the memory location was atomically
ommpy 0:d383e2dee0f7 151 * updated with the desired value (after verifying
ommpy 0:d383e2dee0f7 152 * that it contained the expectedCurrentValue),
ommpy 0:d383e2dee0f7 153 * false otherwise. In the failure case,
ommpy 0:d383e2dee0f7 154 * exepctedCurrentValue is updated with the new
ommpy 0:d383e2dee0f7 155 * value of the target memory location.
ommpy 0:d383e2dee0f7 156 *
ommpy 0:d383e2dee0f7 157 * pseudocode:
ommpy 0:d383e2dee0f7 158 * function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
ommpy 0:d383e2dee0f7 159 * if *p != *old {
ommpy 0:d383e2dee0f7 160 * *old = *p
ommpy 0:d383e2dee0f7 161 * return false
ommpy 0:d383e2dee0f7 162 * }
ommpy 0:d383e2dee0f7 163 * *p = new
ommpy 0:d383e2dee0f7 164 * return true
ommpy 0:d383e2dee0f7 165 * }
ommpy 0:d383e2dee0f7 166 *
ommpy 0:d383e2dee0f7 167 * @note: In the failure case (where the destination isn't set), the value
ommpy 0:d383e2dee0f7 168 * pointed to by expectedCurrentValue is instead updated with the current value.
ommpy 0:d383e2dee0f7 169 * This property helps writing concise code for the following incr:
ommpy 0:d383e2dee0f7 170 *
ommpy 0:d383e2dee0f7 171 * function incr(p : pointer to int, a : int) returns int {
ommpy 0:d383e2dee0f7 172 * done = false
ommpy 0:d383e2dee0f7 173 * value = *p // This fetch operation need not be atomic.
ommpy 0:d383e2dee0f7 174 * while not done {
ommpy 0:d383e2dee0f7 175 * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
ommpy 0:d383e2dee0f7 176 * }
ommpy 0:d383e2dee0f7 177 * return value + a
ommpy 0:d383e2dee0f7 178 * }
ommpy 0:d383e2dee0f7 179 *
ommpy 0:d383e2dee0f7 180 * @note: This corresponds to the C11 "atomic_compare_exchange_strong" - it
ommpy 0:d383e2dee0f7 181 * always succeeds if the current value is expected, as per the pseudocode
ommpy 0:d383e2dee0f7 182 * above; it will not spuriously fail as "atomic_compare_exchange_weak" may.
ommpy 0:d383e2dee0f7 183 */
ommpy 0:d383e2dee0f7 184 bool core_util_atomic_cas_u8(volatile uint8_t *ptr, uint8_t *expectedCurrentValue, uint8_t desiredValue);
ommpy 0:d383e2dee0f7 185
ommpy 0:d383e2dee0f7 186 /**
ommpy 0:d383e2dee0f7 187 * Atomic compare and set. It compares the contents of a memory location to a
ommpy 0:d383e2dee0f7 188 * given value and, only if they are the same, modifies the contents of that
ommpy 0:d383e2dee0f7 189 * memory location to a given new value. This is done as a single atomic
ommpy 0:d383e2dee0f7 190 * operation. The atomicity guarantees that the new value is calculated based on
ommpy 0:d383e2dee0f7 191 * up-to-date information; if the value had been updated by another thread in
ommpy 0:d383e2dee0f7 192 * the meantime, the write would fail due to a mismatched expectedCurrentValue.
ommpy 0:d383e2dee0f7 193 *
ommpy 0:d383e2dee0f7 194 * Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
ommpy 0:d383e2dee0f7 195 * you to the article on compare-and swap].
ommpy 0:d383e2dee0f7 196 *
ommpy 0:d383e2dee0f7 197 * @param ptr The target memory location.
ommpy 0:d383e2dee0f7 198 * @param[in,out] expectedCurrentValue A pointer to some location holding the
ommpy 0:d383e2dee0f7 199 * expected current value of the data being set atomically.
ommpy 0:d383e2dee0f7 200 * The computed 'desiredValue' should be a function of this current value.
ommpy 0:d383e2dee0f7 201 * @note: This is an in-out parameter. In the
ommpy 0:d383e2dee0f7 202 * failure case of atomic_cas (where the
ommpy 0:d383e2dee0f7 203 * destination isn't set), the pointee of expectedCurrentValue is
ommpy 0:d383e2dee0f7 204 * updated with the current value.
ommpy 0:d383e2dee0f7 205 * @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
ommpy 0:d383e2dee0f7 206 *
ommpy 0:d383e2dee0f7 207 * @return true if the memory location was atomically
ommpy 0:d383e2dee0f7 208 * updated with the desired value (after verifying
ommpy 0:d383e2dee0f7 209 * that it contained the expectedCurrentValue),
ommpy 0:d383e2dee0f7 210 * false otherwise. In the failure case,
ommpy 0:d383e2dee0f7 211 * exepctedCurrentValue is updated with the new
ommpy 0:d383e2dee0f7 212 * value of the target memory location.
ommpy 0:d383e2dee0f7 213 *
ommpy 0:d383e2dee0f7 214 * pseudocode:
ommpy 0:d383e2dee0f7 215 * function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
ommpy 0:d383e2dee0f7 216 * if *p != *old {
ommpy 0:d383e2dee0f7 217 * *old = *p
ommpy 0:d383e2dee0f7 218 * return false
ommpy 0:d383e2dee0f7 219 * }
ommpy 0:d383e2dee0f7 220 * *p = new
ommpy 0:d383e2dee0f7 221 * return true
ommpy 0:d383e2dee0f7 222 * }
ommpy 0:d383e2dee0f7 223 *
ommpy 0:d383e2dee0f7 224 * @note: In the failure case (where the destination isn't set), the value
ommpy 0:d383e2dee0f7 225 * pointed to by expectedCurrentValue is instead updated with the current value.
ommpy 0:d383e2dee0f7 226 * This property helps writing concise code for the following incr:
ommpy 0:d383e2dee0f7 227 *
ommpy 0:d383e2dee0f7 228 * function incr(p : pointer to int, a : int) returns int {
ommpy 0:d383e2dee0f7 229 * done = false
ommpy 0:d383e2dee0f7 230 * value = *p // This fetch operation need not be atomic.
ommpy 0:d383e2dee0f7 231 * while not done {
ommpy 0:d383e2dee0f7 232 * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
ommpy 0:d383e2dee0f7 233 * }
ommpy 0:d383e2dee0f7 234 * return value + a
ommpy 0:d383e2dee0f7 235 * }
ommpy 0:d383e2dee0f7 236 *
ommpy 0:d383e2dee0f7 237 * @note: This corresponds to the C11 "atomic_compare_exchange_strong" - it
ommpy 0:d383e2dee0f7 238 * always succeeds if the current value is expected, as per the pseudocode
ommpy 0:d383e2dee0f7 239 * above; it will not spuriously fail as "atomic_compare_exchange_weak" may.
ommpy 0:d383e2dee0f7 240 */
ommpy 0:d383e2dee0f7 241 bool core_util_atomic_cas_u16(volatile uint16_t *ptr, uint16_t *expectedCurrentValue, uint16_t desiredValue);
ommpy 0:d383e2dee0f7 242
ommpy 0:d383e2dee0f7 243 /**
ommpy 0:d383e2dee0f7 244 * Atomic compare and set. It compares the contents of a memory location to a
ommpy 0:d383e2dee0f7 245 * given value and, only if they are the same, modifies the contents of that
ommpy 0:d383e2dee0f7 246 * memory location to a given new value. This is done as a single atomic
ommpy 0:d383e2dee0f7 247 * operation. The atomicity guarantees that the new value is calculated based on
ommpy 0:d383e2dee0f7 248 * up-to-date information; if the value had been updated by another thread in
ommpy 0:d383e2dee0f7 249 * the meantime, the write would fail due to a mismatched expectedCurrentValue.
ommpy 0:d383e2dee0f7 250 *
ommpy 0:d383e2dee0f7 251 * Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
ommpy 0:d383e2dee0f7 252 * you to the article on compare-and swap].
ommpy 0:d383e2dee0f7 253 *
ommpy 0:d383e2dee0f7 254 * @param ptr The target memory location.
ommpy 0:d383e2dee0f7 255 * @param[in,out] expectedCurrentValue A pointer to some location holding the
ommpy 0:d383e2dee0f7 256 * expected current value of the data being set atomically.
ommpy 0:d383e2dee0f7 257 * The computed 'desiredValue' should be a function of this current value.
ommpy 0:d383e2dee0f7 258 * @note: This is an in-out parameter. In the
ommpy 0:d383e2dee0f7 259 * failure case of atomic_cas (where the
ommpy 0:d383e2dee0f7 260 * destination isn't set), the pointee of expectedCurrentValue is
ommpy 0:d383e2dee0f7 261 * updated with the current value.
ommpy 0:d383e2dee0f7 262 * @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
ommpy 0:d383e2dee0f7 263 *
ommpy 0:d383e2dee0f7 264 * @return true if the memory location was atomically
ommpy 0:d383e2dee0f7 265 * updated with the desired value (after verifying
ommpy 0:d383e2dee0f7 266 * that it contained the expectedCurrentValue),
ommpy 0:d383e2dee0f7 267 * false otherwise. In the failure case,
ommpy 0:d383e2dee0f7 268 * exepctedCurrentValue is updated with the new
ommpy 0:d383e2dee0f7 269 * value of the target memory location.
ommpy 0:d383e2dee0f7 270 *
ommpy 0:d383e2dee0f7 271 * pseudocode:
ommpy 0:d383e2dee0f7 272 * function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
ommpy 0:d383e2dee0f7 273 * if *p != *old {
ommpy 0:d383e2dee0f7 274 * *old = *p
ommpy 0:d383e2dee0f7 275 * return false
ommpy 0:d383e2dee0f7 276 * }
ommpy 0:d383e2dee0f7 277 * *p = new
ommpy 0:d383e2dee0f7 278 * return true
ommpy 0:d383e2dee0f7 279 * }
ommpy 0:d383e2dee0f7 280 *
ommpy 0:d383e2dee0f7 281 * @note: In the failure case (where the destination isn't set), the value
ommpy 0:d383e2dee0f7 282 * pointed to by expectedCurrentValue is instead updated with the current value.
ommpy 0:d383e2dee0f7 283 * This property helps writing concise code for the following incr:
ommpy 0:d383e2dee0f7 284 *
ommpy 0:d383e2dee0f7 285 * function incr(p : pointer to int, a : int) returns int {
ommpy 0:d383e2dee0f7 286 * done = false
ommpy 0:d383e2dee0f7 287 * value = *p // This fetch operation need not be atomic.
ommpy 0:d383e2dee0f7 288 * while not done {
ommpy 0:d383e2dee0f7 289 * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
ommpy 0:d383e2dee0f7 290 * }
ommpy 0:d383e2dee0f7 291 * return value + a
ommpy 0:d383e2dee0f7 292 *
ommpy 0:d383e2dee0f7 293 * @note: This corresponds to the C11 "atomic_compare_exchange_strong" - it
ommpy 0:d383e2dee0f7 294 * always succeeds if the current value is expected, as per the pseudocode
ommpy 0:d383e2dee0f7 295 * above; it will not spuriously fail as "atomic_compare_exchange_weak" may.
ommpy 0:d383e2dee0f7 296 * }
ommpy 0:d383e2dee0f7 297 */
ommpy 0:d383e2dee0f7 298 bool core_util_atomic_cas_u32(volatile uint32_t *ptr, uint32_t *expectedCurrentValue, uint32_t desiredValue);
ommpy 0:d383e2dee0f7 299
ommpy 0:d383e2dee0f7 300 /**
ommpy 0:d383e2dee0f7 301 * Atomic compare and set. It compares the contents of a memory location to a
ommpy 0:d383e2dee0f7 302 * given value and, only if they are the same, modifies the contents of that
ommpy 0:d383e2dee0f7 303 * memory location to a given new value. This is done as a single atomic
ommpy 0:d383e2dee0f7 304 * operation. The atomicity guarantees that the new value is calculated based on
ommpy 0:d383e2dee0f7 305 * up-to-date information; if the value had been updated by another thread in
ommpy 0:d383e2dee0f7 306 * the meantime, the write would fail due to a mismatched expectedCurrentValue.
ommpy 0:d383e2dee0f7 307 *
ommpy 0:d383e2dee0f7 308 * Refer to https://en.wikipedia.org/wiki/Compare-and-set [which may redirect
ommpy 0:d383e2dee0f7 309 * you to the article on compare-and swap].
ommpy 0:d383e2dee0f7 310 *
ommpy 0:d383e2dee0f7 311 * @param ptr The target memory location.
ommpy 0:d383e2dee0f7 312 * @param[in,out] expectedCurrentValue A pointer to some location holding the
ommpy 0:d383e2dee0f7 313 * expected current value of the data being set atomically.
ommpy 0:d383e2dee0f7 314 * The computed 'desiredValue' should be a function of this current value.
ommpy 0:d383e2dee0f7 315 * @note: This is an in-out parameter. In the
ommpy 0:d383e2dee0f7 316 * failure case of atomic_cas (where the
ommpy 0:d383e2dee0f7 317 * destination isn't set), the pointee of expectedCurrentValue is
ommpy 0:d383e2dee0f7 318 * updated with the current value.
ommpy 0:d383e2dee0f7 319 * @param[in] desiredValue The new value computed based on '*expectedCurrentValue'.
ommpy 0:d383e2dee0f7 320 *
ommpy 0:d383e2dee0f7 321 * @return true if the memory location was atomically
ommpy 0:d383e2dee0f7 322 * updated with the desired value (after verifying
ommpy 0:d383e2dee0f7 323 * that it contained the expectedCurrentValue),
ommpy 0:d383e2dee0f7 324 * false otherwise. In the failure case,
ommpy 0:d383e2dee0f7 325 * exepctedCurrentValue is updated with the new
ommpy 0:d383e2dee0f7 326 * value of the target memory location.
ommpy 0:d383e2dee0f7 327 *
ommpy 0:d383e2dee0f7 328 * pseudocode:
ommpy 0:d383e2dee0f7 329 * function cas(p : pointer to int, old : pointer to int, new : int) returns bool {
ommpy 0:d383e2dee0f7 330 * if *p != *old {
ommpy 0:d383e2dee0f7 331 * *old = *p
ommpy 0:d383e2dee0f7 332 * return false
ommpy 0:d383e2dee0f7 333 * }
ommpy 0:d383e2dee0f7 334 * *p = new
ommpy 0:d383e2dee0f7 335 * return true
ommpy 0:d383e2dee0f7 336 * }
ommpy 0:d383e2dee0f7 337 *
ommpy 0:d383e2dee0f7 338 * @note: In the failure case (where the destination isn't set), the value
ommpy 0:d383e2dee0f7 339 * pointed to by expectedCurrentValue is instead updated with the current value.
ommpy 0:d383e2dee0f7 340 * This property helps writing concise code for the following incr:
ommpy 0:d383e2dee0f7 341 *
ommpy 0:d383e2dee0f7 342 * function incr(p : pointer to int, a : int) returns int {
ommpy 0:d383e2dee0f7 343 * done = false
ommpy 0:d383e2dee0f7 344 * value = *p // This fetch operation need not be atomic.
ommpy 0:d383e2dee0f7 345 * while not done {
ommpy 0:d383e2dee0f7 346 * done = atomic_cas(p, &value, value + a) // *value gets updated automatically until success
ommpy 0:d383e2dee0f7 347 * }
ommpy 0:d383e2dee0f7 348 * return value + a
ommpy 0:d383e2dee0f7 349 * }
ommpy 0:d383e2dee0f7 350 *
ommpy 0:d383e2dee0f7 351 * @note: This corresponds to the C11 "atomic_compare_exchange_strong" - it
ommpy 0:d383e2dee0f7 352 * always succeeds if the current value is expected, as per the pseudocode
ommpy 0:d383e2dee0f7 353 * above; it will not spuriously fail as "atomic_compare_exchange_weak" may.
ommpy 0:d383e2dee0f7 354 */
ommpy 0:d383e2dee0f7 355 bool core_util_atomic_cas_ptr(void *volatile *ptr, void **expectedCurrentValue, void *desiredValue);
ommpy 0:d383e2dee0f7 356
ommpy 0:d383e2dee0f7 357 /**
ommpy 0:d383e2dee0f7 358 * Atomic increment.
ommpy 0:d383e2dee0f7 359 * @param valuePtr Target memory location being incremented.
ommpy 0:d383e2dee0f7 360 * @param delta The amount being incremented.
ommpy 0:d383e2dee0f7 361 * @return The new incremented value.
ommpy 0:d383e2dee0f7 362 */
ommpy 0:d383e2dee0f7 363 uint8_t core_util_atomic_incr_u8(volatile uint8_t *valuePtr, uint8_t delta);
ommpy 0:d383e2dee0f7 364
ommpy 0:d383e2dee0f7 365 /**
ommpy 0:d383e2dee0f7 366 * Atomic increment.
ommpy 0:d383e2dee0f7 367 * @param valuePtr Target memory location being incremented.
ommpy 0:d383e2dee0f7 368 * @param delta The amount being incremented.
ommpy 0:d383e2dee0f7 369 * @return The new incremented value.
ommpy 0:d383e2dee0f7 370 */
ommpy 0:d383e2dee0f7 371 uint16_t core_util_atomic_incr_u16(volatile uint16_t *valuePtr, uint16_t delta);
ommpy 0:d383e2dee0f7 372
ommpy 0:d383e2dee0f7 373 /**
ommpy 0:d383e2dee0f7 374 * Atomic increment.
ommpy 0:d383e2dee0f7 375 * @param valuePtr Target memory location being incremented.
ommpy 0:d383e2dee0f7 376 * @param delta The amount being incremented.
ommpy 0:d383e2dee0f7 377 * @return The new incremented value.
ommpy 0:d383e2dee0f7 378 */
ommpy 0:d383e2dee0f7 379 uint32_t core_util_atomic_incr_u32(volatile uint32_t *valuePtr, uint32_t delta);
ommpy 0:d383e2dee0f7 380
ommpy 0:d383e2dee0f7 381 /**
ommpy 0:d383e2dee0f7 382 * Atomic increment.
ommpy 0:d383e2dee0f7 383 * @param valuePtr Target memory location being incremented.
ommpy 0:d383e2dee0f7 384 * @param delta The amount being incremented in bytes.
ommpy 0:d383e2dee0f7 385 * @return The new incremented value.
ommpy 0:d383e2dee0f7 386 *
ommpy 0:d383e2dee0f7 387 * @note The type of the pointer argument is not taken into account
ommpy 0:d383e2dee0f7 388 * and the pointer is incremented by bytes.
ommpy 0:d383e2dee0f7 389 */
ommpy 0:d383e2dee0f7 390 void *core_util_atomic_incr_ptr(void *volatile *valuePtr, ptrdiff_t delta);
ommpy 0:d383e2dee0f7 391
ommpy 0:d383e2dee0f7 392 /**
ommpy 0:d383e2dee0f7 393 * Atomic decrement.
ommpy 0:d383e2dee0f7 394 * @param valuePtr Target memory location being decremented.
ommpy 0:d383e2dee0f7 395 * @param delta The amount being decremented.
ommpy 0:d383e2dee0f7 396 * @return The new decremented value.
ommpy 0:d383e2dee0f7 397 */
ommpy 0:d383e2dee0f7 398 uint8_t core_util_atomic_decr_u8(volatile uint8_t *valuePtr, uint8_t delta);
ommpy 0:d383e2dee0f7 399
ommpy 0:d383e2dee0f7 400 /**
ommpy 0:d383e2dee0f7 401 * Atomic decrement.
ommpy 0:d383e2dee0f7 402 * @param valuePtr Target memory location being decremented.
ommpy 0:d383e2dee0f7 403 * @param delta The amount being decremented.
ommpy 0:d383e2dee0f7 404 * @return The new decremented value.
ommpy 0:d383e2dee0f7 405 */
ommpy 0:d383e2dee0f7 406 uint16_t core_util_atomic_decr_u16(volatile uint16_t *valuePtr, uint16_t delta);
ommpy 0:d383e2dee0f7 407
ommpy 0:d383e2dee0f7 408 /**
ommpy 0:d383e2dee0f7 409 * Atomic decrement.
ommpy 0:d383e2dee0f7 410 * @param valuePtr Target memory location being decremented.
ommpy 0:d383e2dee0f7 411 * @param delta The amount being decremented.
ommpy 0:d383e2dee0f7 412 * @return The new decremented value.
ommpy 0:d383e2dee0f7 413 */
ommpy 0:d383e2dee0f7 414 uint32_t core_util_atomic_decr_u32(volatile uint32_t *valuePtr, uint32_t delta);
ommpy 0:d383e2dee0f7 415
ommpy 0:d383e2dee0f7 416 /**
ommpy 0:d383e2dee0f7 417 * Atomic decrement.
ommpy 0:d383e2dee0f7 418 * @param valuePtr Target memory location being decremented.
ommpy 0:d383e2dee0f7 419 * @param delta The amount being decremented in bytes.
ommpy 0:d383e2dee0f7 420 * @return The new decremented value.
ommpy 0:d383e2dee0f7 421 *
ommpy 0:d383e2dee0f7 422 * @note The type of the pointer argument is not taken into account
ommpy 0:d383e2dee0f7 423 * and the pointer is decremented by bytes
ommpy 0:d383e2dee0f7 424 */
ommpy 0:d383e2dee0f7 425 void *core_util_atomic_decr_ptr(void *volatile *valuePtr, ptrdiff_t delta);
ommpy 0:d383e2dee0f7 426
ommpy 0:d383e2dee0f7 427 #ifdef __cplusplus
ommpy 0:d383e2dee0f7 428 } // extern "C"
ommpy 0:d383e2dee0f7 429 #endif
ommpy 0:d383e2dee0f7 430 /**@}*/
ommpy 0:d383e2dee0f7 431
ommpy 0:d383e2dee0f7 432 /**@}*/
ommpy 0:d383e2dee0f7 433
ommpy 0:d383e2dee0f7 434 #endif // __MBED_UTIL_CRITICAL_H__
ommpy 0:d383e2dee0f7 435
ommpy 0:d383e2dee0f7 436
ommpy 0:d383e2dee0f7 437