xv6 style

8253pit.c

@@ -6,34 +6,33 @@
 // 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) */
+#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_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 */
+#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)