3 files changed, 15 insertions(+), 7 deletions(-)

M pc/fns.h
M pc/i8253.c
M port/tod.c

@@ 59,6 59,7 @@ void	kbdinit(void);
 void	lgdt(ushort[3]);
 void	lidt(ushort[3]);
 void	links(void);
+void	loopbackintr(void);
 void	ltr(ulong);
 void	mathinit(void);
 void	meminit(ulong);

@@ 124,10 124,17 @@ i8253init(int aalcycles, int havecycleclock)
 	}
 }
 
+static void
+clockintr0(Ureg* ureg, void *v)
+{
+	loopbackintr();
+	clockintr(ureg, v);
+}
+
 void
 i8253enable(void)
 {
-	intrenable(IrqCLOCK, clockintr, 0, BUSUNKNOWN, "clock");
+	intrenable(IrqCLOCK, clockintr0, 0, BUSUNKNOWN, "clock");
 }
 
 /*

@@ 141,18 141,18 @@ todget(vlong *ticksp)
 }
 
 //
-//  called every clock tick
+//  called every clock tick to avoid calculation overflows
 //
 void
 todfix(void)
 {
-	static ulong last;
+	vlong ticks, diff;
+
+	ticks = fastticks(nil);
 
-	// once a second, make sure we don't overflow
-	if(MACHP(0)->ticks - last >= HZ){
-		last = MACHP(0)->ticks;
+	diff = ticks - tod.last;
+	if(diff > tod.hz)
 		todget(nil);
-	}
 }
 
 long