nuclear@51: #include <stdio.h>
nuclear@51: #include "sched.h"
nuclear@51: #include "proc.h"
nuclear@51: #include "intr.h"
nuclear@51: #include "asmops.h"
nuclear@51: #include "config.h"
nuclear@51: 
nuclear@51: #define EMPTY(q)	((q).head == 0)
nuclear@51: 
nuclear@51: struct proc_list {
nuclear@51: 	struct process *head, *tail;
nuclear@51: };
nuclear@51: 
nuclear@51: static void ins_back(struct proc_list *q, struct process *proc);
nuclear@51: static void ins_front(struct proc_list *q, struct process *proc);
nuclear@51: static void remove(struct proc_list *q, struct process *proc);
nuclear@51: 
nuclear@51: static struct proc_list runq;
nuclear@51: static struct proc_list waitq;
nuclear@51: static struct proc_list zombieq;
nuclear@51: 
nuclear@51: void schedule(void)
nuclear@51: {
nuclear@51: 	if(EMPTY(runq)) {
nuclear@51: 		/* idle "process".
nuclear@51: 		 * make sure interrupts are enabled before halting
nuclear@51: 		 */
nuclear@51: 		enable_intr();
nuclear@51: 		halt_cpu();
nuclear@51: 		/* this won't return, it'll just wake up in an interrupt later */
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	disable_intr();
nuclear@51: 
nuclear@51: 	/* if the current process exhausted its timeslice,
nuclear@51: 	 * move it to the back of the queue.
nuclear@51: 	 */
nuclear@51: 	if(runq.head->ticks_left <= 0) {
nuclear@51: 		if(runq.head->next) {
nuclear@51: 			struct process *proc = runq.head;
nuclear@51: 			remove(&runq, proc);
nuclear@51: 			ins_back(&runq, proc);
nuclear@51: 		}
nuclear@51: 
nuclear@51: 		/* start a new timeslice */
nuclear@51: 		runq.head->ticks_left = TIMESLICE_TICKS;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	/* no need to re-enable interrupts, they will be enabled with the iret */
nuclear@51: 	context_switch(runq.head->id);
nuclear@51: }
nuclear@51: 
nuclear@51: int add_proc(int pid, enum proc_state state)
nuclear@51: {
nuclear@51: 	int istate;
nuclear@51: 	struct proc_list *q;
nuclear@51: 	struct process *proc = get_process(pid);
nuclear@51: 
nuclear@51: 	istate = get_intr_state();
nuclear@51: 	disable_intr();
nuclear@51: 
nuclear@51: 	q = state == STATE_RUNNING ? &runq : &waitq;
nuclear@51: 
nuclear@51: 	ins_back(q, proc);
nuclear@51: 	proc->state = state;
nuclear@51: 
nuclear@51: 	set_intr_state(istate);
nuclear@51: 	return 0;
nuclear@51: }
nuclear@51: 
nuclear@51: int block_proc(int pid)
nuclear@51: {
nuclear@51: 	int istate;
nuclear@51: 	struct process *proc = get_process(pid);
nuclear@51: 
nuclear@51: 	if(proc->state != STATE_RUNNING) {
nuclear@51: 		printf("block_proc: process %d not running\n", pid);
nuclear@51: 		return -1;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	istate = get_intr_state();
nuclear@51: 	disable_intr();
nuclear@51: 
nuclear@51: 	remove(&runq, proc);
nuclear@51: 	ins_back(&waitq, proc);
nuclear@51: 	proc->state = STATE_BLOCKED;
nuclear@51: 
nuclear@51: 	set_intr_state(istate);
nuclear@51: 	return 0;
nuclear@51: }
nuclear@51: 
nuclear@51: int unblock_proc(int pid)
nuclear@51: {
nuclear@51: 	int istate;
nuclear@51: 	struct process *proc = get_process(pid);
nuclear@51: 
nuclear@51: 	if(proc->state != STATE_BLOCKED) {
nuclear@51: 		printf("unblock_proc: process %d not blocked\n", pid);
nuclear@51: 		return -1;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	istate = get_intr_state();
nuclear@51: 	disable_intr();
nuclear@51: 
nuclear@51: 	remove(&waitq, proc);
nuclear@51: 	ins_back(&runq, proc);
nuclear@51: 	proc->state = STATE_RUNNING;
nuclear@51: 
nuclear@51: 	set_intr_state(istate);
nuclear@51: 	return 0;
nuclear@51: }
nuclear@51: 
nuclear@51: 
nuclear@51: static void ins_back(struct proc_list *q, struct process *proc)
nuclear@51: {
nuclear@51: 	if(EMPTY(*q)) {
nuclear@51: 		q->head = proc;
nuclear@51: 	} else {
nuclear@51: 		q->tail->next = proc;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	proc->next = 0;
nuclear@51: 	proc->prev = q->tail;
nuclear@51: 	q->tail = proc;
nuclear@51: }
nuclear@51: 
nuclear@51: static void ins_front(struct proc_list *q, struct process *proc)
nuclear@51: {
nuclear@51: 	if(EMPTY(*q)) {
nuclear@51: 		q->tail = proc;
nuclear@51: 	} else {
nuclear@51: 		q->head->prev = proc;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	proc->next = q->head;
nuclear@51: 	proc->prev = 0;
nuclear@51: 	q->head = proc;
nuclear@51: }
nuclear@51: 
nuclear@51: static void remove(struct proc_list *q, struct process *proc)
nuclear@51: {
nuclear@51: 	if(proc->prev) {
nuclear@51: 		proc->prev->next = proc->next;
nuclear@51: 	}
nuclear@51: 	if(proc->next) {
nuclear@51: 		proc->next->prev = proc->prev;
nuclear@51: 	}
nuclear@51: 	if(q->head == proc) {
nuclear@51: 		q->head = proc->next;
nuclear@51: 	}
nuclear@51: 	if(q->tail == proc) {
nuclear@51: 		q->tail = proc->prev;
nuclear@51: 	}
nuclear@51: }