shared.c

经典的psos编程实例源码

/* shared.c */

#include <psos.h>
#include <prepc.h>
#include <stdio.h>

#include "misc.h"
#include "appl.h"

int	com[5];

void
main_loop(ULONG l1, ULONG l2, ULONG l3, ULONG l4)
{
	char	me[5];
	ULONG	rc, mode;
	int	loop_count, tmp;

	if (rc = t_getreg(0, 0, (ULONG *) me))	/* Get my name */
		fail(rc, "t_getreg()");
	me[5] = '\0';
	for (loop_count = 0; loop_count < LOOP_MAX; loop_count++) {
		/* Try but DO NOT BLOCK on the semaphore.
		   We want to SHOW the user when we can't get it. */
		if (ERR_NOSEM == (rc = sm_p(smid, SM_NOWAIT, 0))) {
			/* Semaphore not available--tell the user */
			bprintf("(%s)", me);
			/* And then wait for it. */
			if (0 != (rc = sm_p(smid, SM_WAIT, 0)))
				fail(rc, "%s sm_p(%08x) failed", me, smid);
		} else if (0 != rc)
			fail(rc, "%s main_loop sm_p(0x%08x)", me, smid);
		/* Regardless, we have the semaphore now */
		bprintf("%s updating: ", me);
		com[0]++;
		if (com[0] & 1) {
			com[1] = com[2]; com[2] = com[3]; com[3]++;
		} else {
			com[1]++; com[2]++;
		}
		tm_wkafter(1+ (rand() % 10)); /* Delay briefly */
		if (com[0] % 5)
			com[3] = 0;
		com[4] = com[0] + com[1] + com[2] + com[3];
		bprintf(" done\n");
		if (0 != (rc = sm_v(smid)))
			fail(rc, "main_loop: %s sm_v(0x%08x)", me, smid);
		tm_wkafter(9 + (rand() % 10)); /* Delay between uses */
	}
	/* Disable task preemption */
	if (rc = t_mode(T_NOPREEMPT, T_NOPREEMPT, & mode))
		fail(rc, "main_loop: %s t_mode #1", me);
	running--;
	/* Re-establish task mode */
	if (rc = t_mode(T_NOPREEMPT, mode, & mode))
		fail(rc, "main_loop: %s t_mode #2", me);
	exit(0);
}