mirror of
https://github.com/yourtion/30dayMakeOS.git
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123 lines
2.8 KiB
C
123 lines
2.8 KiB
C
/* 多任务管理 */
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#include "bootpack.h"
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struct TASKCTL *taskctl;
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struct TIMER *task_timer;
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struct TASK *task_init(struct MEMMAN *memman)
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{
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int i;
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struct TASK *task;
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struct SEGMENT_DESCRIPTOR *gdt = (struct SEGMENT_DESCRIPTOR *) ADR_GDT;
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taskctl = (struct TASKCTL *) memman_alloc_4k(memman, sizeof (struct TASKCTL));
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for (i = 0; i < MAX_TASKS; i++) {
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taskctl->tasks0[i].flags = 0;
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taskctl->tasks0[i].sel = (TASK_GDT0 + i) * 8;
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set_segmdesc(gdt + TASK_GDT0 + i, 103, (int) &taskctl->tasks0[i].tss, AR_TSS32);
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}
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task = task_alloc();
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task->flags = 2; /*活动中标志*/
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task->priority = 2; /* 0.02秒 */
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taskctl->running = 1;
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taskctl->now = 0;
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taskctl->tasks[0] = task;
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load_tr(task->sel);
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task_timer = timer_alloc();
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timer_settime(task_timer, task->priority);
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return task;
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}
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struct TASK *task_alloc(void)
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{
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int i;
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struct TASK *task;
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for (i = 0; i < MAX_TASKS; i++) {
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if (taskctl->tasks0[i].flags == 0) {
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task = &taskctl->tasks0[i];
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task->flags = 1; /*正在使用的标志*/
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task->tss.eflags = 0x00000202; /* IF = 1; */
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task->tss.eax = 0; /*这里先置为0*/
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task->tss.ecx = 0;
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task->tss.edx = 0;
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task->tss.ebx = 0;
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task->tss.ebp = 0;
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task->tss.esi = 0;
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task->tss.edi = 0;
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task->tss.es = 0;
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task->tss.ds = 0;
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task->tss.fs = 0;
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task->tss.gs = 0;
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task->tss.ldtr = 0;
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task->tss.iomap = 0x40000000;
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return task;
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}
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}
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return 0; /*全部正在使用*/
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}
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void task_run(struct TASK *task, int priority)
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{
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if (priority > 0) {
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task->priority = priority;
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}
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if (task->flags != 2) {
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task->flags = 2; /*活动中标志*/
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taskctl->tasks[taskctl->running] = task;
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taskctl->running++;
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}
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return;
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}
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void task_switch(void){
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struct TASK *task;
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taskctl->now++;
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if (taskctl->now == taskctl->running) {
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taskctl->now = 0;
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}
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task = taskctl->tasks[taskctl->now];
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timer_settime(task_timer, task->priority);
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if (taskctl->running >= 2) {
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farjmp(0, task->sel);
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}
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return;
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}
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void task_sleep(struct TASK *task)
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{
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int i;
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char ts = 0;
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if (task->flags == 2) { /*如果指定任务处于唤醒状态*/
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if (task == taskctl->tasks[taskctl->now]) {
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ts = 1; /*让自己休眠的话，稍后需要进行任务切换*/
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}
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/*寻找task所在的位置*/
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for (i = 0; i < taskctl->running; i++) {
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if (taskctl->tasks[i] == task) {
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/*在这里*/
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break;
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}
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}
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taskctl->running--;
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if (i < taskctl->now) {
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taskctl->now--; /*需要移动成员，要相应地处理*/
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}
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/*移动成员*/
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for (; i < taskctl->running; i++) {
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taskctl->tasks[i] = taskctl->tasks[i + 1];
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}
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task->flags = 1; /*不工作的状态*/
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if (ts != 0) {
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/*任务切换*/
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if (taskctl->now >= taskctl->running) {
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/*如果now的值出现异常，则进行修正*/
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taskctl->now = 0;
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}
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farjmp(0, taskctl->tasks[taskctl->now]->sel);
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}
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}
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return;
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}
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