89 lines
1.7 KiB
C
89 lines
1.7 KiB
C
#include <scheduler.h>
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#include <list.h>
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#include <debug.h>
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#include <sse.h>
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LIST(thread_t, ready_queue);
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thread_t *scheduler_th;
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thread_t *last_thread = 0;
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#define get_last_thread() (last_thread)
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#define set_last_thread(new) (last_thread = (new))
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void scheduler_insert(thread_t *th)
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{
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// Append thread to the ready queue and prepare it for running
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LIST_APPEND(ready_queue, th, ready_queue);
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th->state = THREAD_STATE_READY;
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}
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void scheduler_remove(thread_t *th)
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{
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// Remove thread from the ready queue
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LIST_REMOVE(ready_queue, th, ready_queue);
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}
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thread_t *scheduler_next()
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{
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// Get the next thread from the ready queue
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if(!LIST_EMPTY(ready_queue))
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{
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thread_t *th = LIST_FIRST(ready_queue);
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scheduler_remove(th);
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return th;
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}
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return 0;
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}
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void scheduler()
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{
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while(1)
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{
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thread_t *old = 0, *new = 0;
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if((old = get_last_thread()))
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{
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if(old->state != THREAD_STATE_FINISHED && process_alive(old->process))
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{
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old->state = THREAD_STATE_READY;
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scheduler_insert(old);
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} else {
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old->state = THREAD_STATE_FINISHED;
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}
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}
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while(!(new = scheduler_next()));
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if(!process_alive(new->process))
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{
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new->state = THREAD_STATE_FINISHED;
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continue;
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}
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new->state = THREAD_STATE_RUNNING;
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set_last_thread(new);
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switch_process(new->process);
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sse_restore(new->sse_registers);
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switch_thread(scheduler_th, new);
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}
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}
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void schedule()
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{
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// This function handles swithing to the next thread in the ready queue
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thread_t *old = get_current_thread();
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if(old)
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{
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sse_save(old->sse_registers);
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}
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switch_process(0);
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switch_thread(old, scheduler_th);
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}
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void scheduler_init()
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{
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LIST_HEAD_INIT(ready_queue);
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scheduler_th = new_thread(scheduler);
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}
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