--- xinu/sys/sleep.c	2018/04/24 17:39:04	1.1.1.1
+++ xinu/sys/sleep.c	2018/04/24 17:39:55	1.1.1.2
@@ -13,14 +13,15 @@
 SYSCALL	sleep(n)
 	int	n;
 {
-	PStype	ps;
-
+#ifdef	DEBUG
+	dotrace("sleep", &n, 1);
+#endif
 	if (n<0 || clkruns==0)
 		return(SYSERR);
 	if (n == 0) {
-		disable(ps);
-		resched();
-		restore(ps);
+	        disable();
+		resched();	/* resched assumes caller is disabled */
+		restore();
 		return(OK);
 	}
 	while (n >= 1000) {