TIMER.C

#include <dos.h>
#include <stdio.h>
int a = 0;
int b = 0;
int c = 1;
void interrupt clocktick(){
    b++;
    outp(0x20, 0x20);
    outp(0x36, 0x43);
}
int main(void){
    /* set PIT mode*/
    outp(0x36, 0x43);
    outp(0x01,0x40); /* send low byte*/
    outp(0x00,0x40); /* send high byte*/
    setvect(0x08, clocktick);
    while(c == 1){
        printf("b%i\n", b);
    }
    getchar();
    return 0;
}