Add libmthread and test59 to test the implementation

lib/libmthread/queue.c

@@ -0,0 +1,105 @@
+#include <minix/mthread.h>
+#include "global.h"
+
+/*===========================================================================*
+ *				mthread_queue_add			     *
+ *===========================================================================*/
+PUBLIC void mthread_queue_add(queue, thread)
+mthread_queue_t *queue;		/* Queue we want thread to append to */
+mthread_thread_t thread;
+{
+/* Append a thread to the tail of the queue. As a process can be present on
+ * only one queue at the same time, we can use the threads array's 'next'
+ * pointer to point to the next thread on the queue.
+ */
+
+  if (mthread_queue_isempty(queue)) {
+	queue->head = queue->tail = thread;
+  } else {
+	threads[queue->tail].m_next = thread;
+	queue->tail = thread; /* 'thread' is the new last in line */
+  }
+}
+
+
+/*===========================================================================*
+ *				mthread_queue_init			     *
+ *===========================================================================*/
+PUBLIC void mthread_queue_init(queue)
+mthread_queue_t *queue;		/* Queue that has to be initialized */
+{
+/* Initialize queue to a known state */
+
+  queue->head = queue->tail = NO_THREAD;
+}
+
+
+/*===========================================================================*
+ *				mthread_queue_isempty			     *
+ *===========================================================================*/
+PUBLIC int mthread_queue_isempty(queue)
+mthread_queue_t *queue;
+{
+  return(queue->head == NO_THREAD);
+}
+
+
+/*===========================================================================*
+ *				mthread_dump_queue			     *
+ *===========================================================================*/
+PUBLIC void mthread_dump_queue(queue)
+mthread_queue_t *queue;
+{
+  int threshold, count = 0;
+  mthread_thread_t t;
+  threshold = no_threads;
+#ifdef MDEBUG
+  printf("Dumping queue: ");
+#endif
+  if(queue->head != NO_THREAD) {
+  	t = queue->head;
+#ifdef MDEBUG
+	printf("%d ", t);
+#endif
+	count++;
+	t = threads[t].m_next;
+	while (t != NO_THREAD) {
+#ifdef MDEBUG
+		printf("%d ", t);
+#endif
+		t = threads[t].m_next;
+		count++;
+		if (count > threshold) break;
+	}
+  } else {
+#ifdef MDEBUG
+  	printf("[empty]");
+#endif
+  }
+
+#ifdef MDEBUG
+  printf("\n");
+#endif
+}
+
+
+/*===========================================================================*
+ *				mthread_queue_remove			     *
+ *===========================================================================*/
+PUBLIC mthread_thread_t mthread_queue_remove(queue)
+mthread_queue_t *queue;		/* Queue we want a thread from */
+{
+/* Get the first thread in this queue, if there is one. */
+  mthread_thread_t thread = queue->head;
+
+  if (thread != NO_THREAD) { /* i.e., this queue is not empty */
+	if (queue->head == queue->tail) /* Queue holds only one thread */
+		queue->head = queue->tail = NO_THREAD; /*So mark thread empty*/
+	else
+		/* Second thread in line is the new first */
+		queue->head = threads[thread].m_next;
+  }
+
+  return(thread);
+}
+