1 files changed, 41 insertions, 0 deletions
diff --git a/os/port/alarm.c b/os/port/alarm.c
new file mode 100644
index 00000000..4f7662c3
--- /dev/null
+++ b/os/port/alarm.c
@@ -0,0 +1,41 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+
+Talarm	talarm;
+
+/*
+ *  called every clock tick
+ */
+void
+checkalarms(void)
+{
+	Proc *p;
+	ulong now;
+
+	now = MACHP(0)->ticks;
+
+	if(talarm.list == 0 || canlock(&talarm) == 0)
+		return;
+
+	for(;;) {
+		p = talarm.list;
+		if(p == 0)
+			break;
+
+		if(p->twhen == 0) {
+			talarm.list = p->tlink;
+			p->trend = 0;
+			continue;
+		}
+		if(now < p->twhen)
+			break;
+		wakeup(p->trend);
+		talarm.list = p->tlink;
+		p->trend = 0;
+	}
+
+	unlock(&talarm);
+}