Add 26 day code

26_day/timer.c

@@ -0,0 +1,169 @@
+/* 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;
+	struct TIMER *t;
+	io_out8(PIT_CTRL, 0x34);
+	io_out8(PIT_CNT0, 0x9c);
+	io_out8(PIT_CNT0, 0x2e);
+	timerctl.count = 0;
+	for (i = 0; i < MAX_TIMER; i++) {
+		timerctl.timers0[i].flags = 0; /* 没有使用 */
+	}
+	t = timer_alloc(); /* 取得一个 */
+	t->timeout = 0xffffffff;
+	t->flags = TIMER_FLAGS_USING;
+	t->next = 0; /* 末尾 */
+	timerctl.t0 = t; /* 因为现在只有哨兵，所以他就在最前面*/
+	timerctl.next = 0xffffffff; /* 因为只有哨兵，所以下一个超时时刻就是哨兵的时刻 */
+	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;
+			timerctl.timers0[i].flags2 = 0;
+			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 FIFO32 *fifo, int data)
+{
+	timer->fifo = fifo;
+	timer->data = data;
+	return;
+}
+
+void timer_settime(struct TIMER *timer, unsigned int timeout)
+{
+	int e;
+	struct TIMER *t, *s;
+	timer->timeout = timeout + timerctl.count;
+	timer->flags = TIMER_FLAGS_USING;
+	e = io_load_eflags();
+	io_cli();
+	t = timerctl.t0;
+	if (timer->timeout <= t->timeout) {
+	/* 插入最前面的情况 */
+		timerctl.t0 = timer;
+		timer->next = t; /* 下面是设定t */
+		timerctl.next = timer->timeout;
+		io_store_eflags(e);
+		return;
+	}
+	for (;;) {
+		s = t;
+		t = t->next;
+		if (timer->timeout <= t->timeout) {
+		/* 插入s和t之间的情况 */
+			s->next = timer; /* s下一个是timer */
+			timer->next = t; /* timer的下一个是t */
+			io_store_eflags(e);
+			return;
+		}
+	}
+}
+
+void inthandler20(int *esp)
+{
+	struct TIMER *timer;
+	char ts = 0;
+	io_out8(PIC0_OCW2, 0x60); /* 把IRQ-00接收信号结束的信息通知给PIC */
+	timerctl.count++;
+	if (timerctl.next > timerctl.count) {
+		return;
+	}
+	timer = timerctl.t0; /* 首先把最前面的地址赋给timer */
+	for (;;) {
+	/* 因为timers的定时器都处于运行状态，所以不确认flags */
+		if (timer->timeout > timerctl.count) {
+			break;
+		}
+		/* 超时 */
+		timer->flags = TIMER_FLAGS_ALLOC;
+		if (timer != task_timer) {
+			fifo32_put(timer->fifo, timer->data);
+		} else {
+			ts = 1; /* mt_timer超时*/
+		}
+		timer = timer->next; /* 将下一个定时器的地址赋给timer*/
+	}
+	timerctl.t0 = timer;
+	timerctl.next = timer->timeout;
+	if (ts != 0) {
+		task_switch();
+	}
+	return;
+}
+
+int timer_cancel(struct TIMER *timer)
+{
+	int e;
+	struct TIMER *t;
+	e = io_load_eflags();
+	io_cli(); /*在设置过程中禁止改变定时器状态*/
+	if (timer->flags == TIMER_FLAGS_USING) { /*是否需要取消？*/
+		if (timer == timerctl.t0) {
+			/*第一个定时器的取消处理*/
+			t = timer->next;
+			timerctl.t0 = t;
+			timerctl.next = t->timeout;
+		} else {
+			/*非第一个定时器的取消处理*/
+			/*找到timer前一个定时器*/
+			t = timerctl.t0;
+			for (;;) {
+				if (t->next == timer) {
+					break;
+				}
+				t = t->next;
+			}
+			t->next = timer->next; 
+			/*将之前“timer的下一个”指向“timer的下一个”*/
+		}
+		timer->flags = TIMER_FLAGS_ALLOC;
+		io_store_eflags(e);
+		return 1; /*取消处理成功*/
+	}
+	io_store_eflags(e);
+	return 0; /*不需要取消处理*/
+}
+
+void timer_cancelall(struct FIFO32 *fifo)
+{
+	int e, i;
+	struct TIMER *t;
+	e = io_load_eflags();
+	io_cli(); /*在设置过程中禁止改变定时器状态*/
+	for (i = 0; i < MAX_TIMER; i++) {
+		t = &timerctl.timers0[i];
+		if (t->flags != 0 && t->flags2 != 0 && t->fifo == fifo) {
+			timer_cancel(t);
+			timer_free(t);
+		}
+	}
+	io_store_eflags(e);
+	return;
+}