/* 定时器 */

#include "bootpack.h"

#define PIT_CTRL	0x0043
#define PIT_CNT0	0x0040

struct TIMERCTL timerctl;

#define TIMER_FLAGS_ALLOC 1 /* 已配置状态 */
#define TIMER_FLAGS_USING 2 /* 定时器运行中 */

void init_pit(void)
{
	int i;
	io_out8(PIT_CTRL, 0x34);
	io_out8(PIT_CNT0, 0x9c);
	io_out8(PIT_CNT0, 0x2e);
	timerctl.count = 0;
	timerctl.next = 0xffffffff; /* 因为最初没有正在运行的定时器 */
	timerctl.using = 0;
	for (i = 0; i < MAX_TIMER; i++) {
	timerctl.timers0[i].flags = 0; /* 未使用 */
	}
	return;
}

struct TIMER *timer_alloc(void)
{
	int i;
	for (i = 0; i < MAX_TIMER; i++) {
		if (timerctl.timers0[i].flags == 0) {
			timerctl.timers0[i].flags = TIMER_FLAGS_ALLOC;
			return &timerctl.timers0[i];
		}
	}
	return 0; /* 没找到 */
}

void timer_free(struct TIMER *timer)
{
	timer->flags = 0; /* 未使用 */
	return;
}

void timer_init(struct TIMER *timer, struct FIFO8 *fifo, unsigned char data)
{
	timer->fifo = fifo;
	timer->data = data;
	return;
}

void timer_settime(struct TIMER *timer, unsigned int timeout)
{
	int e, i, j;
	timer->timeout = timeout + timerctl.count;
	timer->flags = TIMER_FLAGS_USING;
	e = io_load_eflags();
	io_cli();
	/* 搜索注册位置 */
	for (i = 0; i < timerctl.using; i++) {
		if (timerctl.timers[i]->timeout >= timer->timeout) {
			break;
		}
	}
	/* i号之后全部后移一位 */
	for (j = timerctl.using; j > i; j--) {
		timerctl.timers[j] = timerctl.timers[j - 1];
	}
	timerctl.using++;
	/* 插入到空位上 */
	timerctl.timers[i] = timer;
	timerctl.next = timerctl.timers[0]->timeout;
	io_store_eflags(e);
	return;
}

void inthandler20(int *esp)
{
	int i, j;
	io_out8(PIC0_OCW2, 0x60); /* 把IRQ-00信号接收完了的信息通知给PIC */
	timerctl.count++;
	if (timerctl.next > timerctl.count) {
		return; /* 还不到下一个时刻，所以结束*/
	}
	timerctl.next = 0xffffffff;
	for (i = 0; i < timerctl.using; i++) {
		/* timers的定时器都处于动作中，所以不确认flags */
		if (timerctl.timers[i]->timeout > timerctl.count) {
			break;
		}
		/* 超时*/
		timerctl.timers[i]->flags = TIMER_FLAGS_ALLOC;
		fifo8_put(timerctl.timers[i]->fifo, timerctl.timers[i]->data);
	}
	/* 正好有i个定时器超时了。其余的进行移位。 */
	timerctl.using -= i;
	for (j = 0; j < timerctl.using; j++) {
		timerctl.timers[j] = timerctl.timers[i + j];
	}
	if (timerctl.using > 0) {
		timerctl.next = timerctl.timers[0]->timeout;
	} else {
		timerctl.next = 0xffffffff;
	}
	return;
}