Renamed src/lib/utils to src/lib/sysutil --- because of new src/lib/util

lib/sysutil/tickdelay.c

@@ -0,0 +1,43 @@
+#include "sysutil.h"
+
+/*===========================================================================*
+ *                               tickdelay			    	     *
+ *===========================================================================*/
+PUBLIC int tickdelay(ticks)
+long ticks;				/* number of ticks to wait */
+{
+/* This function uses the synchronous alarm to delay for a while. This works
+ * even if a previous synchronous alarm was scheduled, because the remaining
+ * tick of the previous alarm are returned so that it can be rescheduled.
+ * Note however that a long tick_delay (longer than the remaining time of the
+ * previous) alarm will also delay the previous alarm.
+ */
+    message m, m_alarm;
+    clock_t time_left;
+    int s;
+
+    if (ticks <= 0) return;		/* check for robustness */
+
+    m.ALRM_PROC_NR = SELF;		/* SELF means this process nr */
+    m.ALRM_EXP_TIME = ticks;		/* request message after ticks */
+    m.ALRM_ABS_TIME = 0;		/* ticks are relative to now */
+    s = _taskcall(SYSTASK, SYS_SETALARM, &m);
+    if (s != OK) return(s);
+
+    receive(CLOCK,&m_alarm);		/* await synchronous alarm */
+
+    /* Check if we must reschedule the current alarm. */
+    if (m.ALRM_TIME_LEFT > 0) {
+    	m.ALRM_EXP_TIME = m.ALRM_TIME_LEFT - ticks;
+    	if (m.ALRM_EXP_TIME <= 0) 
+    		m.ALRM_EXP_TIME = 1;
+    	s = _taskcall(SYSTASK, SYS_SETALARM, &m);
+    }
+
+    return(s);
+}
+
+
+
+
+