120 lines
3.4 KiB
C
120 lines
3.4 KiB
C
#include <minix/mthread.h>
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#include "global.h"
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#include "proto.h"
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/*===========================================================================*
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* mthread_queue_add *
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*===========================================================================*/
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PUBLIC void mthread_queue_add(queue, thread)
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mthread_queue_t *queue; /* Queue we want thread to append to */
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mthread_thread_t thread;
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{
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/* Append a thread to the tail of the queue. As a process can be present on
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* only one queue at the same time, we can use the threads array's 'next'
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* pointer to point to the next thread on the queue.
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*/
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mthread_tcb_t *last;
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if (!isokthreadid(thread))
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mthread_panic("Can't append invalid thread ID to a queue");
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last = mthread_find_tcb(thread);
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if (mthread_queue_isempty(queue)) {
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queue->mq_head = queue->mq_tail = last;
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} else {
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queue->mq_tail->m_next = last;
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queue->mq_tail = last; /* 'last' is the new last in line */
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}
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}
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/*===========================================================================*
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* mthread_queue_init *
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*===========================================================================*/
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PUBLIC void mthread_queue_init(queue)
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mthread_queue_t *queue; /* Queue that has to be initialized */
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{
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/* Initialize queue to a known state */
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queue->mq_head = queue->mq_tail = NULL;
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}
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/*===========================================================================*
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* mthread_queue_isempty *
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*===========================================================================*/
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PUBLIC int mthread_queue_isempty(queue)
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mthread_queue_t *queue;
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{
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return(queue->mq_head == NULL);
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}
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/*===========================================================================*
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* mthread_dump_queue *
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*===========================================================================*/
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#ifdef MDEBUG
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PUBLIC void mthread_dump_queue(queue)
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mthread_queue_t *queue;
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{
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int threshold, count = 0;
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mthread_tcb_t *t;
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mthread_thread_t tid;
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threshold = no_threads;
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printf("Dumping queue: ");
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if(queue->mq_head != NULL) {
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t = queue->mq_head;
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if (t == &mainthread) tid = MAIN_THREAD;
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else tid = t->m_tid;
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printf("%d ", tid);
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count++;
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t = t->m_next;
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while (t != NULL) {
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if (t == &mainthread) tid = MAIN_THREAD;
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else tid = t->m_tid;
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printf("%d ", tid);
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t = t->m_next;
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count++;
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if (count > threshold) break;
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}
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} else {
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printf("[empty]");
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}
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printf("\n");
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}
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#endif
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/*===========================================================================*
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* mthread_queue_remove *
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*===========================================================================*/
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PUBLIC mthread_thread_t mthread_queue_remove(queue)
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mthread_queue_t *queue; /* Queue we want a thread from */
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{
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/* Get the first thread in this queue, if there is one. */
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mthread_thread_t thread;
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mthread_tcb_t *tcb;
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/* Calculate thread id from queue head */
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if (queue->mq_head == NULL) thread = NO_THREAD;
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else if (queue->mq_head == &mainthread) thread = MAIN_THREAD;
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else thread = (queue->mq_head->m_tid);
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if (thread != NO_THREAD) { /* i.e., this queue is not empty */
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tcb = queue->mq_head;
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if (queue->mq_head == queue->mq_tail) {
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/* Queue holds only one thread */
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queue->mq_head = queue->mq_tail = NULL; /* So mark thread empty */
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} else {
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/* Second thread in line is the new first */
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queue->mq_head = queue->mq_head->m_next;
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}
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tcb->m_next = NULL; /* This thread is no longer part of a queue */
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}
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return(thread);
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}
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