run without lapic and ioapic, if they are not present

if no lapic available, use 8253pit for clock
now xv6 runs both on qemu (uniprocessor) and bochs (uniprocessor and MP)

1 files changed, 1 insertions, 1 deletions

diff --git a/traps.h b/traps.h
index b1bafa0..732d8e0 100644
--- a/traps.h
+++ b/traps.h
@@ -27,8 +27,8 @@
 
 #define IRQ_OFFSET      32      // IRQ 0 corresponds to int IRQ_OFFSET
 
+#define IRQ_TIMER        0
 #define IRQ_KBD          1
 #define IRQ_IDE         14
-#define IRQ_TIMER       18
 #define IRQ_ERROR       19
 #define IRQ_SPURIOUS    31