mirror of
https://github.com/yourtion/30dayMakeOS.git
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110 lines
2.5 KiB
C
110 lines
2.5 KiB
C
/* 定时器 */
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#include "bootpack.h"
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#define PIT_CTRL 0x0043
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#define PIT_CNT0 0x0040
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struct TIMERCTL timerctl;
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#define TIMER_FLAGS_ALLOC 1 /* 已配置状态 */
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#define TIMER_FLAGS_USING 2 /* 定时器运行中 */
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void init_pit(void)
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{
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int i;
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struct TIMER *t;
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io_out8(PIT_CTRL, 0x34);
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io_out8(PIT_CNT0, 0x9c);
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io_out8(PIT_CNT0, 0x2e);
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timerctl.count = 0;
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for (i = 0; i < MAX_TIMER; i++) {
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timerctl.timers0[i].flags = 0; /* 没有使用 */
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}
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t = timer_alloc(); /* 取得一个 */
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t->timeout = 0xffffffff;
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t->flags = TIMER_FLAGS_USING;
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t->next = 0; /* 末尾 */
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timerctl.t0 = t; /* 因为现在只有哨兵，所以他就在最前面*/
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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 */
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return;
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}
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struct TIMER *timer_alloc(void)
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{
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int i;
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for (i = 0; i < MAX_TIMER; i++) {
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if (timerctl.timers0[i].flags == 0) {
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timerctl.timers0[i].flags = TIMER_FLAGS_ALLOC;
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return &timerctl.timers0[i];
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}
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}
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return 0; /* 没找到 */
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}
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void timer_free(struct TIMER *timer)
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{
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timer->flags = 0; /* 未使用 */
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return;
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}
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void timer_init(struct TIMER *timer, struct FIFO32 *fifo, int data)
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{
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timer->fifo = fifo;
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timer->data = data;
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return;
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}
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void timer_settime(struct TIMER *timer, unsigned int timeout)
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{
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int e;
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struct TIMER *t, *s;
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timer->timeout = timeout + timerctl.count;
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timer->flags = TIMER_FLAGS_USING;
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e = io_load_eflags();
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io_cli();
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t = timerctl.t0;
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if (timer->timeout <= t->timeout) {
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/* 插入最前面的情况 */
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timerctl.t0 = timer;
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timer->next = t; /* 下面是设定t */
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timerctl.next = timer->timeout;
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io_store_eflags(e);
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return;
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}
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for (;;) {
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s = t;
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t = t->next;
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if (timer->timeout <= t->timeout) {
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/* 插入s和t之间的情况 */
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s->next = timer; /* s下一个是timer */
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timer->next = t; /* timer的下一个是t */
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io_store_eflags(e);
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return;
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}
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}
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}
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void inthandler20(int *esp)
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{
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struct TIMER *timer;
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io_out8(PIC0_OCW2, 0x60); /* 把IRQ-00接收信号结束的信息通知给PIC */
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timerctl.count++;
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if (timerctl.next > timerctl.count) {
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return;
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}
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timer = timerctl.t0; /* 首先把最前面的地址赋给timer */
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for (;;) {
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/* 因为timers的定时器都处于运行状态，所以不确认flags */
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if (timer->timeout > timerctl.count) {
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break;
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}
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/* 超时 */
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timer->flags = TIMER_FLAGS_ALLOC;
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fifo32_put(timer->fifo, timer->data);
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timer = timer->next; /* 将下一个定时器的地址赋给timer*/
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}
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timerctl.t0 = timer;
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timerctl.next = timer->timeout;
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return;
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} |