48 lines
1016 B
C
48 lines
1016 B
C
#include <x86.h>
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#include <kern/process.h>
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#include <kern/protect.h>
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#include <kern/trap.h>
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/*
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* 调度函数
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*/
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void
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schedule(void)
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{
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// 如果中断没关，一定！一定！一定！要关中断保证当前执行流操作的原子性
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DISABLE_INT();
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PROCESS *p_cur_proc = p_proc_ready;
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PROCESS *p_next_proc = p_proc_ready;
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asm volatile ("":::"memory");
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static bool in_sche;
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if (in_sche)
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goto free;
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in_sche = true;
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do {
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if (++p_next_proc >= proc_table + PCB_SIZE)
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p_next_proc = proc_table;
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if (p_cur_proc == p_next_proc &&
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p_next_proc->pcb.statu != READY) {
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asm volatile("sti\n\thlt\n\tcli":::"memory");
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}
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} while (p_next_proc->pcb.statu != READY);
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p_proc_ready = p_next_proc;
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// 切换进程页表和tss
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lcr3(p_proc_ready->pcb.cr3);
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tss.esp0 = (u32)(&p_proc_ready->pcb.user_regs + 1);
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in_sche = false;
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switch_kern_context(
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&p_cur_proc->pcb.kern_regs,
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&p_next_proc->pcb.kern_regs);
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asm volatile ("":::"memory");
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free:
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ENABLE_INT();
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} |