Christopher Haster / events

Note! This project has moved to github.com/armmbed/mbed-events

Dependents:   SimpleHTTPExample

This repository has been superceded

This project has moved to mbed-events

Composable event loops combine the cheap synchronicity of event loops with the composability of preempted threads.

Two modular event queue classes are provided:

  • EventLoop - for loops coupled with a c++ managed thread
  • EventQueue - for manually managed event queues

The Event class takes advantage of the extensibility of FuncPtr to allow an event to be passed through APIs as a normal function.

More information on composable event loops.

EventQueue.cpp@17:6d564266850e, 2016-04-18 (annotated)

Committer:
Christopher Haster
Date:
Mon Apr 18 12:51:04 2016 -0500
Revision:
17:6d564266850e
Parent:
16:ff5d48fcce1b
Child:
20:2f9d9c53a5af
Add convenience trigger functions

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Christopher Haster 2:11cda6bead99 1 #include "EventQueue.h"
Christopher Haster 2:11cda6bead99 2 #include "Event.h"
Christopher Haster 10:62767e708bb6 3 #include "mbed.h"
Christopher Haster 9:2b0910397844 4 #include "rtos.h"
Christopher Haster 9:2b0910397844 5
Christopher Haster 0:b1b901ae3696 6
Christopher Haster 15:92d7c0b8a0f5 7 // Platform specific definitions
Christopher Haster 15:92d7c0b8a0f5 8 static inline unsigned irq_disable() {
Christopher Haster 15:92d7c0b8a0f5 9 unsigned primask = __get_PRIMASK();
Christopher Haster 15:92d7c0b8a0f5 10 __disable_irq();
Christopher Haster 15:92d7c0b8a0f5 11 return primask;
Christopher Haster 15:92d7c0b8a0f5 12 }
Christopher Haster 14:5abf2ccf2dbf 13
Christopher Haster 15:92d7c0b8a0f5 14 static inline void irq_enable(unsigned primask) {
Christopher Haster 15:92d7c0b8a0f5 15 __set_PRIMASK(primask);
Christopher Haster 15:92d7c0b8a0f5 16 }
Christopher Haster 15:92d7c0b8a0f5 17
Christopher Haster 15:92d7c0b8a0f5 18
Christopher Haster 15:92d7c0b8a0f5 19 // Event queue definitions
Christopher Haster 14:5abf2ccf2dbf 20 EventQueue::EventQueue(unsigned event_count, unsigned event_context) {
Christopher Haster 14:5abf2ccf2dbf 21 _event_context = sizeof(FuncPtr<void()>) + event_context;
Christopher Haster 14:5abf2ccf2dbf 22 unsigned event_size = sizeof(struct event) + _event_context;
Christopher Haster 14:5abf2ccf2dbf 23 _mem = malloc(event_count * event_size);
Christopher Haster 14:5abf2ccf2dbf 24 _free = (struct event*)_mem;
Christopher Haster 14:5abf2ccf2dbf 25
Christopher Haster 14:5abf2ccf2dbf 26 if (_mem) {
Christopher Haster 14:5abf2ccf2dbf 27 for (unsigned i = 0; i < event_count-1; i++) {
Christopher Haster 14:5abf2ccf2dbf 28 ((struct event*)((char*)_mem + i*event_size))->next =
Christopher Haster 14:5abf2ccf2dbf 29 (struct event*)((char*)_mem + (i+1)*event_size);
Christopher Haster 14:5abf2ccf2dbf 30 }
Christopher Haster 14:5abf2ccf2dbf 31 ((struct event*)((char*)_mem + (event_count-1)*event_size))->next = 0;
Christopher Haster 14:5abf2ccf2dbf 32 }
Christopher Haster 14:5abf2ccf2dbf 33
Christopher Haster 5:9963a617f952 34 _queue = 0;
Christopher Haster 2:11cda6bead99 35 _tick = 0;
Christopher Haster 2:11cda6bead99 36 _timer.start();
Christopher Haster 2:11cda6bead99 37 _ticker.attach_us(this, &EventQueue::tick, (1 << 16) * 1000);
Christopher Haster 2:11cda6bead99 38 }
Christopher Haster 2:11cda6bead99 39
Christopher Haster 14:5abf2ccf2dbf 40 EventQueue::~EventQueue() {
Christopher Haster 14:5abf2ccf2dbf 41 free(_mem);
Christopher Haster 14:5abf2ccf2dbf 42 }
Christopher Haster 14:5abf2ccf2dbf 43
Christopher Haster 2:11cda6bead99 44 unsigned EventQueue::get_tick() {
Christopher Haster 2:11cda6bead99 45 return _tick + (unsigned)_timer.read_ms();
Christopher Haster 2:11cda6bead99 46 }
Christopher Haster 2:11cda6bead99 47
Christopher Haster 16:ff5d48fcce1b 48 bool EventQueue::past_tick(unsigned tick) {
Christopher Haster 16:ff5d48fcce1b 49 return static_cast<int>(tick - get_tick()) <= 0;
Christopher Haster 16:ff5d48fcce1b 50 }
Christopher Haster 16:ff5d48fcce1b 51
Christopher Haster 2:11cda6bead99 52 void EventQueue::tick() {
Christopher Haster 2:11cda6bead99 53 _timer.reset();
Christopher Haster 2:11cda6bead99 54 _tick += 1 << 16;
Christopher Haster 2:11cda6bead99 55 }
Christopher Haster 2:11cda6bead99 56
Christopher Haster 1:2202c19570e5 57 void EventQueue::dispatch(int ms) {
Christopher Haster 16:ff5d48fcce1b 58 unsigned target = get_tick() + (unsigned)ms;
Christopher Haster 0:b1b901ae3696 59
Christopher Haster 0:b1b901ae3696 60 while (true) {
Christopher Haster 0:b1b901ae3696 61 while (_queue) {
Christopher Haster 16:ff5d48fcce1b 62 if (!past_tick(_queue->target)) {
Christopher Haster 2:11cda6bead99 63 break;
Christopher Haster 2:11cda6bead99 64 }
Christopher Haster 2:11cda6bead99 65
Christopher Haster 16:ff5d48fcce1b 66 unsigned primask = irq_disable();
Christopher Haster 2:11cda6bead99 67 struct event *volatile e = _queue;
Christopher Haster 0:b1b901ae3696 68 _queue = _queue->next;
Christopher Haster 16:ff5d48fcce1b 69 irq_enable(primask);
Christopher Haster 2:11cda6bead99 70
Christopher Haster 14:5abf2ccf2dbf 71 e->dispatch(reinterpret_cast<void *>(e + 1));
Christopher Haster 2:11cda6bead99 72
Christopher Haster 2:11cda6bead99 73 if (e->period >= 0) {
Christopher Haster 17:6d564266850e 74 event_trigger(e, e->period);
Christopher Haster 14:5abf2ccf2dbf 75 } else {
Christopher Haster 17:6d564266850e 76 event_dealloc(e);
Christopher Haster 2:11cda6bead99 77 }
Christopher Haster 0:b1b901ae3696 78 }
Christopher Haster 0:b1b901ae3696 79
Christopher Haster 16:ff5d48fcce1b 80 if (ms >= 0 && past_tick(target)) {
Christopher Haster 16:ff5d48fcce1b 81 return;
Christopher Haster 15:92d7c0b8a0f5 82 }
Christopher Haster 15:92d7c0b8a0f5 83
Christopher Haster 16:ff5d48fcce1b 84 osStatus status = Thread::yield();
Christopher Haster 16:ff5d48fcce1b 85 if (status != osOK) {
Christopher Haster 16:ff5d48fcce1b 86 return;
Christopher Haster 16:ff5d48fcce1b 87 }
Christopher Haster 0:b1b901ae3696 88 }
Christopher Haster 0:b1b901ae3696 89 }
Christopher Haster 0:b1b901ae3696 90
Christopher Haster 17:6d564266850e 91 void EventQueue::event_trigger(struct event *e, int delay) {
Christopher Haster 14:5abf2ccf2dbf 92 e->target = get_tick() + (unsigned)delay;
Christopher Haster 2:11cda6bead99 93
Christopher Haster 15:92d7c0b8a0f5 94 unsigned primask = irq_disable();
Christopher Haster 2:11cda6bead99 95 struct event *volatile *p = &_queue;
Christopher Haster 14:5abf2ccf2dbf 96 while (*p && (*p)->target < e->target) {
Christopher Haster 2:11cda6bead99 97 p = &(*p)->next;
Christopher Haster 0:b1b901ae3696 98 }
Christopher Haster 2:11cda6bead99 99
Christopher Haster 14:5abf2ccf2dbf 100 e->next = *p;
Christopher Haster 14:5abf2ccf2dbf 101 *p = e;
Christopher Haster 15:92d7c0b8a0f5 102 irq_enable(primask);
Christopher Haster 0:b1b901ae3696 103 }
Christopher Haster 0:b1b901ae3696 104
Christopher Haster 17:6d564266850e 105 EventQueue::event *EventQueue::event_alloc(unsigned size, int ms) {
Christopher Haster 14:5abf2ccf2dbf 106 if (size > _event_context) {
Christopher Haster 14:5abf2ccf2dbf 107 return 0;
Christopher Haster 14:5abf2ccf2dbf 108 }
Christopher Haster 14:5abf2ccf2dbf 109
Christopher Haster 16:ff5d48fcce1b 110 unsigned target = get_tick() + (unsigned)ms;
Christopher Haster 14:5abf2ccf2dbf 111 struct event *e;
Christopher Haster 14:5abf2ccf2dbf 112
Christopher Haster 16:ff5d48fcce1b 113 while (true) {
Christopher Haster 16:ff5d48fcce1b 114 if (_free) {
Christopher Haster 16:ff5d48fcce1b 115 unsigned primask = irq_disable();
Christopher Haster 16:ff5d48fcce1b 116 if (_free) {
Christopher Haster 16:ff5d48fcce1b 117 e = _free;
Christopher Haster 16:ff5d48fcce1b 118 _free = _free->next;
Christopher Haster 16:ff5d48fcce1b 119 }
Christopher Haster 16:ff5d48fcce1b 120 irq_enable(primask);
Christopher Haster 16:ff5d48fcce1b 121 }
Christopher Haster 16:ff5d48fcce1b 122
Christopher Haster 16:ff5d48fcce1b 123 if (e || (ms >= 0 && past_tick(target))) {
Christopher Haster 16:ff5d48fcce1b 124 return e;
Christopher Haster 16:ff5d48fcce1b 125 }
Christopher Haster 16:ff5d48fcce1b 126
Christopher Haster 16:ff5d48fcce1b 127 osStatus status = Thread::yield();
Christopher Haster 16:ff5d48fcce1b 128 if (status != osOK) {
Christopher Haster 16:ff5d48fcce1b 129 return e;
Christopher Haster 16:ff5d48fcce1b 130 }
Christopher Haster 0:b1b901ae3696 131 }
Christopher Haster 0:b1b901ae3696 132 }
Christopher Haster 0:b1b901ae3696 133
Christopher Haster 17:6d564266850e 134 void EventQueue::event_dealloc(struct event *e) {
Christopher Haster 15:92d7c0b8a0f5 135 unsigned primask = irq_disable();
Christopher Haster 14:5abf2ccf2dbf 136 e->next = _free;
Christopher Haster 14:5abf2ccf2dbf 137 _free = e;
Christopher Haster 15:92d7c0b8a0f5 138 irq_enable(primask);
Christopher Haster 14:5abf2ccf2dbf 139 }
Christopher Haster 14:5abf2ccf2dbf 140