/* Handhaben des sio-Interrupts */
/* Datei: sioint2.c */

#include <stdio.h>
#include <dos.h>
#include <conio.h>
static int sioadr[4] = { 0x3f8,0x2f8,0x3e8,0x2e8 };
static int sioint[4] = { 4,    3,    4,    3 };
static int comindex;
enum sioregs{ DATA, IER, IIR, LCR, MCR, LSR, MSR, SRC};
enum picregs{ IMR=0x21,OCW1=0x21,OCW2=0x20,OCW3=0x20};
typedef void interrupt (*isra)();
isra oldint;
volatile int got_int = 0;
volatile unsigned long count = 0;
void interrupt shandler ()
{ count++;
  got_int = 1;
  inportb(sioadr[comindex] + DATA);
  outportb (OCW2,0x20); /* Allgemeiner EOI */
}
void installint (int comno)
{ int x = sioint[comno] +8;
  oldint = getvect(x);
  setvect(x, shandler);
}
void restoreint(int comno)
{ setvect (sioint[comno]+8, oldint);
}
int main ()
{ comindex = 0;
  installint (comindex);
  while (!kbhit())
   { if (got_int)
      { got_int = 0;
      printf ("\r%06ld",count);
      }
   }
  printf ("\nZõhler ist %ld",count);
  restoreint(comindex);
  return 0;
}