Mayank Gupta / Mbed OS pelion-example-frdm

Example

Dependencies:   FXAS21002 FXOS8700Q

simple-mbed-cloud-client/mbed-cloud-client/update-client-hub/modules/atomic-queue/source/atomic.h@0:11cc2b7889af, 2019-11-19 (annotated)

Committer:
maygup01
Date:
Tue Nov 19 09:49:38 2019 +0000
Revision:
0:11cc2b7889af
Example

Who changed what in which revision?

UserRevisionLine numberNew contents of line
maygup01 0:11cc2b7889af 1 // ----------------------------------------------------------------------------
maygup01 0:11cc2b7889af 2 // Copyright 2015-2017 ARM Ltd.
maygup01 0:11cc2b7889af 3 //
maygup01 0:11cc2b7889af 4 // SPDX-License-Identifier: Apache-2.0
maygup01 0:11cc2b7889af 5 //
maygup01 0:11cc2b7889af 6 // Licensed under the Apache License, Version 2.0 (the "License");
maygup01 0:11cc2b7889af 7 // you may not use this file except in compliance with the License.
maygup01 0:11cc2b7889af 8 // You may obtain a copy of the License at
maygup01 0:11cc2b7889af 9 //
maygup01 0:11cc2b7889af 10 // http://www.apache.org/licenses/LICENSE-2.0
maygup01 0:11cc2b7889af 11 //
maygup01 0:11cc2b7889af 12 // Unless required by applicable law or agreed to in writing, software
maygup01 0:11cc2b7889af 13 // distributed under the License is distributed on an "AS IS" BASIS,
maygup01 0:11cc2b7889af 14 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
maygup01 0:11cc2b7889af 15 // See the License for the specific language governing permissions and
maygup01 0:11cc2b7889af 16 // limitations under the License.
maygup01 0:11cc2b7889af 17 // ----------------------------------------------------------------------------
maygup01 0:11cc2b7889af 18
maygup01 0:11cc2b7889af 19 #ifndef ATOMIC_QUEUE_ATOMIC_H
maygup01 0:11cc2b7889af 20 #define ATOMIC_QUEUE_ATOMIC_H
maygup01 0:11cc2b7889af 21 #include <stdint.h>
maygup01 0:11cc2b7889af 22
maygup01 0:11cc2b7889af 23
maygup01 0:11cc2b7889af 24
maygup01 0:11cc2b7889af 25 #ifdef __cplusplus
maygup01 0:11cc2b7889af 26 extern "C" {
maygup01 0:11cc2b7889af 27 #endif
maygup01 0:11cc2b7889af 28
maygup01 0:11cc2b7889af 29 enum {
maygup01 0:11cc2b7889af 30 AQ_ATOMIC_CAS_DEREF_SUCCESS = 0,
maygup01 0:11cc2b7889af 31 AQ_ATOMIC_CAS_DEREF_NULLPTR,
maygup01 0:11cc2b7889af 32 AQ_ATOMIC_CAS_DEREF_VALUE,
maygup01 0:11cc2b7889af 33 AQ_ATOMIC_CAS_DEREF_INTERUPTED,
maygup01 0:11cc2b7889af 34 };
maygup01 0:11cc2b7889af 35
maygup01 0:11cc2b7889af 36 /**
maygup01 0:11cc2b7889af 37 * @brief Atomically compares the value of a dereferenced pointer, replacing the pointer on success.
maygup01 0:11cc2b7889af 38 * @detail aq_atomic_cas_deref_uintptr provides a mechanism to atomically change a pointer based on a value contained
maygup01 0:11cc2b7889af 39 * in the structure referenced by the pointer. This is done in the following sequence of operations:
maygup01 0:11cc2b7889af 40 *
maygup01 0:11cc2b7889af 41 * 1. Load the value of `*ptrAddr`
maygup01 0:11cc2b7889af 42 * 2. Optionally store the current value of `*ptrAddr`
maygup01 0:11cc2b7889af 43 * 3. Check that the pointer is valid: `*ptrAddr != NULL`
maygup01 0:11cc2b7889af 44 * 4. Check the value of the referenced location: `*(*ptrAddr + valueOffset) == expectedDerefValue` (casts omitted)
maygup01 0:11cc2b7889af 45 * 5. If 3 and 4 succeeded, store newPtrValue: `*ptrAddr = newPtrValue` (NOTE: in non-blocking implementations, this step can fail)
maygup01 0:11cc2b7889af 46 * 6. Return a status code based on the results of 3, 4, 5.
maygup01 0:11cc2b7889af 47 *
maygup01 0:11cc2b7889af 48 * @param[in,out] ptrAddr The address of the pointer to manipulate
maygup01 0:11cc2b7889af 49 * @param[out] currentPtrValue A pointer to a container for the current value of *ptrAddr
maygup01 0:11cc2b7889af 50 * @param[in] expectedDerefValue This is the value that is expected at *(uintptr_t *)((uintptr_t)*ptrAddr + valueOffset)
maygup01 0:11cc2b7889af 51 * @param[in] newPtrValue The value to store to *ptrAddr if the comparison is successful
maygup01 0:11cc2b7889af 52 * @param[in] valueOffset The offset of the target value from *ptrAddr
maygup01 0:11cc2b7889af 53 *
maygup01 0:11cc2b7889af 54 * @retval AQ_ATOMIC_CAS_DEREF_SUCCESS The compare and set has succeeded
maygup01 0:11cc2b7889af 55 * @retval AQ_ATOMIC_CAS_DEREF_NULLPTR `*ptrAddr` was `NULL`
maygup01 0:11cc2b7889af 56 * @retval AQ_ATOMIC_CAS_DEREF_VALUE The value test failed (*(*ptrAddr + valueOffset) != expectedDerefValue`)
maygup01 0:11cc2b7889af 57 * @retval AQ_ATOMIC_CAS_DEREF_INTERUPTED Another context modified `*ptrAddr`
maygup01 0:11cc2b7889af 58 */
maygup01 0:11cc2b7889af 59 int aq_atomic_cas_deref_uintptr(uintptr_t *volatile *ptrAddr,
maygup01 0:11cc2b7889af 60 uintptr_t **currentPtrValue,
maygup01 0:11cc2b7889af 61 uintptr_t expectedDerefValue,
maygup01 0:11cc2b7889af 62 uintptr_t *newPtrValue,
maygup01 0:11cc2b7889af 63 uintptr_t valueOffset);
maygup01 0:11cc2b7889af 64
maygup01 0:11cc2b7889af 65 #ifdef __cplusplus
maygup01 0:11cc2b7889af 66 } // extern "C"
maygup01 0:11cc2b7889af 67 #endif
maygup01 0:11cc2b7889af 68 #endif // ATOMIC_QUEUE_ATOMIC_H