mbed library sources for airmote
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Diff: capi/us_ticker_api.c
- Revision:
- 4:c4bfb462ca53
- Child:
- 6:6dfdb79ccc45
diff -r c24f5ba8a7f9 -r c4bfb462ca53 capi/us_ticker_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/capi/us_ticker_api.c Wed Mar 13 15:04:05 2013 +0000 @@ -0,0 +1,113 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include <stddef.h> +#include "us_ticker_api.h" + +static ticker_event_handler event_handler; +static ticker_event_t *head = NULL; + +void us_ticker_set_handler(ticker_event_handler handler) { + us_ticker_init(); + + event_handler = handler; +} + +void us_ticker_irq_handler(void) { + us_ticker_clear_interrupt(); + + /* Go through all the pending TimerEvents */ + while (1) { + if (head == NULL) { + // There are no more TimerEvents left, so disable matches. + us_ticker_disable_interrupt(); + return; + } + + if ((int)(head->timestamp - us_ticker_read()) <= 0) { + // This event was in the past: + // point to the following one and execute its handler + ticker_event_t *p = head; + head = head->next; + if (event_handler != NULL) { + event_handler(p->id); // NOTE: the handler can set new events + } + } else { + // This event and the following ones in the list are in the future: + // set it as next interrupt and return + us_ticker_set_interrupt(head->timestamp); + return; + } + } +} + +void us_ticker_insert_event(ticker_event_t *obj, unsigned int timestamp, uint32_t id) { + /* disable interrupts for the duration of the function */ + __disable_irq(); + + // initialise our data + obj->timestamp = timestamp; + obj->id = id; + + /* Go through the list until we either reach the end, or find + an element this should come before (which is possibly the + head). */ + ticker_event_t *prev = NULL, *p = head; + while (p != NULL) { + /* check if we come before p */ + if ((int)(timestamp - p->timestamp) <= 0) { + break; + } + /* go to the next element */ + prev = p; + p = p->next; + } + /* if prev is NULL we're at the head */ + if (prev == NULL) { + head = obj; + us_ticker_set_interrupt(timestamp); + } else { + prev->next = obj; + } + /* if we're at the end p will be NULL, which is correct */ + obj->next = p; + + __enable_irq(); +} + +void us_ticker_remove_event(ticker_event_t *obj) { + __disable_irq(); + + // remove this object from the list + if (head == obj) { + // first in the list, so just drop me + head = obj->next; + if (obj->next != NULL) { + us_ticker_set_interrupt(head->timestamp); + } + } else { + // find the object before me, then drop me + ticker_event_t* p = head; + while (p != NULL) { + if (p->next == obj) { + p->next = obj->next; + break; + } + p = p->next; + } + } + + __enable_irq(); +}