os

Toy OS
git clone git://git.margiolis.net/os.git
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timer.c (679B)

      1 #include <libc.h>
      2 #include "libk.h"
      3 #include "idt.h"
      4 #include "io.h"
      5 
      6 #define TIMER_CMD	0x43
      7 #define TIMER_DATA	0x40
      8 #define SQUARE_WAVE	0x36
      9 #define FREQ		1193180
     10 #define HZ		100
     11 
     12 static void timer_callback(struct regs *);
     13 
     14 static u_int32_t ticks = 0;
     15 
     16 static void
     17 timer_callback(struct regs *r)
     18 {
     19 	ticks++;
     20 	UNUSED(r);
     21 }
     22 
     23 void
     24 timer_init(void)
     25 {
     26 	u_int32_t div = FREQ / HZ;
     27 
     28 	intr_register_handler(IRQ0, timer_callback);
     29 	/* Repating mode. */
     30 	outb(TIMER_CMD, SQUARE_WAVE);
     31 	outb(TIMER_DATA, (u_int8_t)(div & 0xff));
     32 	outb(TIMER_DATA, (u_int8_t)(div >> 8));
     33 	printf("timer on irq 0\n");
     34 
     35 	/*outb(TIMER_CMD, SQUARE_WAVE);*/
     36 	/*outb(TIMER_DATA, 0);*/
     37 	/*outb(TIMER_DATA, 0);*/
     38 }