fix bug in handling the timer interrupt

=> sending EOI before task switching

arch/x86/kernel/irq.c

@@ -253,7 +253,7 @@ void irq_handler(struct state *s)
 	 */
 	if (apic_is_enabled() || s->int_no >= 123) {
 		apic_eoi();
-		return;
+		goto leave_handler;
 	}
 
 #ifndef CONFIG_ROCKCREEK
@@ -273,4 +273,9 @@ void irq_handler(struct state *s)
 #else
 	kprintf("Upps, RockCreek uses IRQs below 123!\n");
 #endif
+
+leave_handler:
+	// timer interrupt?
+	if ((s->int_no == 32) || (s->int_no == 123))
+		scheduler(); // 	switch to a new task
 }

arch/x86/kernel/timer.c

@@ -69,15 +69,12 @@ static void timer_handler(struct state *s)
 #endif
 
 	/* 
-         * Every TIMER_FREQ clocks (approximately 1 second), we will
+	 * Every TIMER_FREQ clocks (approximately 1 second), we will
 	 * display a message on the screen 
-         */
+	 */
 	/*if (timer_ticks % TIMER_FREQ == 0) {
 		vga_puts("One second has passed\n");
 	}*/
-
-	// switch to a new task
-	scheduler();
 }
 
 /*