new-task.c

static void _task_entry_point(uint32_t part0, uint32_t part1)
{
	union ptr_splitter p;
	p.part[0] = part0;
	p.part[1] = part1;
	task_t *task = (task_t*)p.ptr;
	task->fn(task);
	task->done = 1;
	swapcontext(&task->schd->callee, &task->schd->caller);
}

static task_t* taskcreate(schd_t* const schd, task_fn_t fn)
{
	task_t *task = (task_t*)calloc(1, sizeof(task_t));

	task->schd = schd;
	task->stack = (char*)calloc(1, default_stack_size);
	task->fn = fn;

	getcontext(&task->context);
	task->context.uc_stack.ss_sp = task->stack;
	task->context.uc_stack.ss_size = default_stack_size;
	task->context.uc_link = 0;

	union ptr_splitter p;
	p.ptr = task;
	makecontext(&task->context, (void (*)(void))_task_entry_point, 2, p.part[0], p.part[1]);
	return task;
}

static void addtask(schd_t* const schd, task_t* const t)
{
	if (schd->tail)
	{
		schd->tail->next = t;
		t->prev = schd->tail;
	} else {
		schd->head = t;
		t->prev = 0;
	}
	schd->tail = t;
	t->next = 0;
}

static void taskfree(task_t* const task)
{
	task_t* waitfor = task->waitfor;
	while (waitfor)
	{
		task_t* const next = waitfor->next;
		addtask(task->schd, waitfor);
		waitfor = next;
	}
	free(task->stack);
	free(task);
}