diff --git a/8253pit.c b/8253pit.c
deleted file mode 100644
index 1d98dc1..0000000
--- a/8253pit.c
+++ /dev/null
@@ -1,45 +0,0 @@
-#include "types.h"
-#include "defs.h"
-#include "traps.h"
-#include "x86.h"
-
-// Register definitions for the Intel
-// 8253/8254/82C54 Programmable Interval Timer (PIT).
-
-#define IO_TIMER1       0x040           // 8253 Timer #1
-#define IO_TIMER2       0x048           // 8253 Timer #2 (EISA only)
-
-// Frequency of all three count-down timers; (TIMER_FREQ/freq) is the
-// appropriate count to generate a frequency of freq hz.
-
-#define TIMER_FREQ      1193182
-#define TIMER_DIV(x)    ((TIMER_FREQ+(x)/2)/(x))
-
-#define TIMER_CNTR0     (IO_TIMER1 + 0) // timer 0 counter port
-#define TIMER_CNTR1     (IO_TIMER1 + 1) // timer 1 counter port
-#define TIMER_CNTR2     (IO_TIMER1 + 2) // timer 2 counter port
-#define TIMER_MODE      (IO_TIMER1 + 3) // timer mode port
-#define TIMER_SEL0      0x00    // select counter 0
-#define TIMER_SEL1      0x40    // select counter 1
-#define TIMER_SEL2      0x80    // select counter 2
-#define TIMER_INTTC     0x00    // mode 0, intr on terminal cnt
-#define TIMER_ONESHOT   0x02    // mode 1, one shot
-#define TIMER_RATEGEN   0x04    // mode 2, rate generator
-#define TIMER_SQWAVE    0x06    // mode 3, square wave
-#define TIMER_SWSTROBE  0x08    // mode 4, s/w triggered strobe
-#define TIMER_HWSTROBE  0x0a    // mode 5, h/w triggered strobe
-#define TIMER_LATCH     0x00    // latch counter for reading
-#define TIMER_LSB       0x10    // r/w counter LSB
-#define TIMER_MSB       0x20    // r/w counter MSB
-#define TIMER_16BIT     0x30    // r/w counter 16 bits, LSB first
-#define TIMER_BCD       0x01    // count in BCD
-
-void
-pit8253_timerinit(void)
-{
-  // initialize 8253 clock to interrupt 100 times/sec
-  outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
-  outb(IO_TIMER1, TIMER_DIV(100) % 256);
-  outb(IO_TIMER1, TIMER_DIV(100) / 256);
-  irq_enable(IRQ_TIMER);
-}
diff --git a/defs.h b/defs.h
index a86a9be..a72ecaf 100644
--- a/defs.h
+++ b/defs.h
@@ -7,9 +7,6 @@ struct proc;
 struct spinlock;
 struct stat;
 
-// 8253pit.c
-void            pit8253_timerinit(void);
-
 // bio.c
 void            binit(void);
 struct buf*     bread(uint, uint);
@@ -140,6 +137,9 @@ int             fetchint(struct proc*, uint, int*);
 int             fetchstr(struct proc*, uint, char**);
 void            syscall(void);
 
+// timer.c
+void            timer_init(void);
+
 // trap.c
 void            idtinit(void);
 extern int      ticks;
diff --git a/main.c b/main.c
index a7570bc..87e5841 100644
--- a/main.c
+++ b/main.c
@@ -46,7 +46,7 @@ main(void)
   ide_init();      // disk
   bootothers();    // boot other CPUs
   if(!ismp)
-    pit8253_timerinit(); // uniprocessor timer
+    timer_init(); // uniprocessor timer
   userinit();      // first user process
 
   // enable interrupts on this processor.
@@ -74,7 +74,7 @@ mpmain(void)
   scheduler();
 }
 
-void
+static void
 bootothers(void)
 {
   extern uchar _binary_bootother_start[], _binary_bootother_size[];
diff --git a/runoff.list b/runoff.list
index 9064544..7a2a390 100644
--- a/runoff.list
+++ b/runoff.list
@@ -64,7 +64,7 @@ picirq.c
 kbd.h
 kbd.c
 console.c
-8253pit.c
+timer.c
 
 # user-level
 usys.S
diff --git a/timer.c b/timer.c
new file mode 100644
index 0000000..ba4e6c4
--- /dev/null
+++ b/timer.c
@@ -0,0 +1,32 @@
+// Intel 8253/8254/82C54 Programmable Interval Timer (PIT).
+// Only used on uniprocessors;
+// SMP machines use the local APIC timer.
+
+#include "types.h"
+#include "defs.h"
+#include "traps.h"
+#include "x86.h"
+
+#define IO_TIMER1       0x040           // 8253 Timer #1
+
+// Frequency of all three count-down timers;
+// (TIMER_FREQ/freq) is the appropriate count
+// to generate a frequency of freq Hz.
+
+#define TIMER_FREQ      1193182
+#define TIMER_DIV(x)    ((TIMER_FREQ+(x)/2)/(x))
+
+#define TIMER_MODE      (IO_TIMER1 + 3) // timer mode port
+#define TIMER_SEL0      0x00    // select counter 0
+#define TIMER_RATEGEN   0x04    // mode 2, rate generator
+#define TIMER_16BIT     0x30    // r/w counter 16 bits, LSB first
+
+void
+timer_init(void)
+{
+  // Interrupt 100 times/sec.
+  outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
+  outb(IO_TIMER1, TIMER_DIV(100) % 256);
+  outb(IO_TIMER1, TIMER_DIV(100) / 256);
+  irq_enable(IRQ_TIMER);
+}