/* Handhaben des sio-Interrupts */
/* Datei: sioint4.c */

#include <stdio.h>
#include <dos.h>
#include <string.h>
#include <conio.h>

#define COMUSED 1

struct SIO
{
int base;
char intno;
char intmask;
};
typedef struct SIO sio;
enum sioregs{DATA, IER, IIR, LCR, MCR, LSR, MSR, SRC};
enum picregs{IMR=0x21,OCW1=0x21,OCW2=0x20,OCW3=0x20};

typedef void interrupt (*isra)(void);
void interrupt shandler();

sio s8250[4] = {
	{ 0x3f8, 4, 0x10 },
	{ 0x2f8, 3, 0x08 },
	{ 0x3e8, 4, 0x10 },
	{ 0x2e8, 3, 0x08 }
	};

isra oldint;
volatile int got_int = 0;
volatile int test[4] = { 0,0,0,0 };
int comindex;
volatile unsigned int count = 0;

void interrupt shandler (void)
{ register int x;
  count++;
  got_int = 1;
  do {
    x = inportb (s8250[comindex].base + IIR);
    if (x & 1)
       break;
    switch (x >> 1)
     {
     case 0: 	/* Modem Status */
	     test[0]++;
	     x=inportb(s8250[comindex].base+MSR);
	     break;
     case 1: 	/* Sendeinterrupt */
	     test[1]++; break;
     case 2: 	/* Empfangsdaten */
	     test[2]++;	/* data received */
	     x=inportb(s8250[comindex].base+DATA);
	     break;
     case 3: 	/* Empfangsstatus */
	     test[3]++;
	     x=inportb(s8250[comindex].base+LSR);
	     if (x & 1)
		x=inportb(s8250[comindex].base+DATA);
	     break;
     }
  } while (1);
  outportb (OCW2,0x20);   /* non specific EOI */
}

int sioSetParam(sio *sp,int bd,int bit,int pr,int st)
{
union
 {
 unsigned short int i16;
 unsigned char b[2];
 } takt;
unsigned char x;
if (bd < 300 || bd > 19200)
  return -2;
if (bit < 5 || bit > 8)
  return -3;
if (st < 1 || st > 2)
  return -4;
if (strchr ("nNmMEeOoSs",pr) == NULL)
  return -5;
x = bit -5;   	/* bit 0 /bit 1*/
if (st == 2)
   x = x | 0x4; /* bit 2 */
if (strchr("nN",pr) == NULL)
   {
   x = x | 0x08;  /* bit 3 */
   if (strchr ("eEsS",pr) != NULL)
      x = x | 0x10;
   if (strchr ("mMsS",pr) != NULL)
      x = x | 0x20;
   }
takt.i16 = 115200L / bd;
outportb(sp->base +LCR,inportb(sp->base + LCR) |0x80);
outportb(sp->base,takt.b[0]);  /* LSB */
outportb(sp->base +1,takt.b[1]);/* MSB */
outportb(sp->base +LCR ,x);
return takt.i16;
}

void installint (sio * sp)
{
/* Interrupt am 8259a abschalten */
char y;
y = inportb (IMR);
y = y | sp->intmask;
outportb (IMR,y);
y = 99;
outportb (OCW2, 0x0b);
y = inportb (OCW2);
if (y & sp->intmask)
  {		/* R³cksetzen Interrupt */
  outportb (OCW2,0x60 | sp->intno);
  }
oldint = getvect(sp->intno +8);
setvect(sp->intno +8, shandler);
sioSetParam (sp, 1200, 7,'n',1);
outportb(sp->base +MCR,0x0b); /* set dtr, rts out2 */
y= y*5;
outportb (sp->base + IER, 5);
y = inportb (IMR);
y = y &~sp->intmask;
outportb (IMR,y);
}

void restoreint(sio * sp)
{
/* Interrupt am 8259a abschalten */
char y;
y = inportb (IMR);
y = y | sp->intmask;
outportb (IMR,y);
outportb (sp->base +IIR,0);
setvect (sp->intno +8, oldint);
}

int main ()
{
int i;
comindex = COMUSED -1;
clrscr();
printf ("\nTest der SIO Interrupts \n\n");
installint (& s8250[comindex]);
while (!kbhit())
   {if (got_int)
      {
      got_int = 0;
      printf ("\r%06d",count);
      }
   }
printf ("\n\nZõhler ist %d\n",count);
restoreint(&s8250[comindex]);
for (i = 0; i < 4; i++)
  printf ("\nTEST: = %d-Werte %d",i,test[i]);
printf ("\n\nProgrammende.\n");
return 0;
}