#include <stdio.h>
#include <dos.h>
#include <conio.h>
//#include "irq.h"
unsigned ADDRESS;
typedef unsigned int uint;
int flag = 0;
int byte = 0;
unsigned IRQ;

void interrupt far (*oldisr[16])(__CPPARGS);  //global to store old handler pointer

unsigned char initirq(char IRQnumber,void interrupt (*ISR)())
{
   unsigned char intmask, oldmask;

   if (IRQnumber <=7) {
      oldmask = inportb(0x21);
      oldisr[IRQnumber] = getvect(IRQnumber + 8);
      setvect(IRQnumber + 8,ISR);
      intmask = oldmask & (~(1 << IRQnumber));
      outportb(0x21,intmask);
   } else {
      oldmask = inportb(0xA1);
      oldisr[IRQnumber] = getvect(IRQnumber + 0x70 - 8);
      setvect(IRQnumber - 8 + 0x70, ISR);
      intmask = oldmask & (~(1 << (IRQnumber - 8)));
      outportb(0xA1, intmask);
   }
   return(oldmask);
}

void restoreirq(char IRQnumber)
{
   unsigned char intmask;

   if (IRQnumber <=7 ){
      intmask = inportb(0x21);
      intmask |= (1 << IRQnumber);
      setvect(IRQnumber + 8, oldisr[IRQnumber]);
      outportb(0x21, intmask);
   } else {
      intmask = inportb(0xA1);
      intmask |= (1 << (IRQnumber - 8));
      setvect(IRQnumber - 8 + 0x70, oldisr[IRQnumber]);
      outportb(0xA1, intmask);
   }
}


unsigned AskForBaseAddress(unsigned int OldOne)
{
	char msg[7];
	int NewOne = 0, Success = 0, Dummy;
	int AddrInputPosX, AddrInputPosY;

	puts("\nPlease enter the Base Address for your card (in hex)");
	printf("or press ENTER for %X.\n>", OldOne);
	AddrInputPosX = wherex(); AddrInputPosY = wherey();
	do {
      gotoxy(AddrInputPosX, AddrInputPosY);
      clreol();
      msg[0] = 6; msg[1] = 0;
      cgets(msg);
      sscanf(msg + 2, "%x", &NewOne);
      Success = 1;
      Dummy = NewOne;
		if (msg[1] == 0) {
        gotoxy(AddrInputPosX, AddrInputPosY);
        printf("%X", OldOne);
        Success = 1;
        Dummy = OldOne;
      }
	} while(!Success);
	return (Dummy);
} /* end of AskForBaseAddress */


unsigned AskForBaseIRQ(unsigned int OldOne)
{
	char msg[7];
	int NewOne = 0, Success = 0, Dummy;
	int AddrInputPosX, AddrInputPosY;

	puts("\nPlease enter the IRQ for your card (in hex)");
	printf("or press ENTER for %X.\n>", OldOne);
	AddrInputPosX = wherex(); AddrInputPosY = wherey();
	do {
      gotoxy(AddrInputPosX, AddrInputPosY);
      clreol();
      msg[0] = 3; msg[1] = 0;
      cgets(msg);
      sscanf(msg + 2, "%x", &NewOne);
      Success = 1;
      Dummy = NewOne;
		if (msg[1] == 0) {
        gotoxy(AddrInputPosX, AddrInputPosY);
        printf("%X", OldOne);
        Success = 1;
        Dummy = OldOne;
      }
	} while(!Success);
	return (Dummy);
} // end of AskForBaseIRQ

void CtrMode(uint addr, char cntr, char mode)
{
  int ctrl;
  ctrl = (cntr << 6) | 0x30 | (mode << 1);
  outportb(addr+3,ctrl);
}

void CtrLoad(uint addr ,int c,int val)
{
  outportb(addr+c,val & 0x00FF);
  outportb(addr+c,(val>>8) & 0x00FF);
}



void interrupt setflag()
{
  flag=1;       //read character
  byte = inportb(ADDRESS+4);
  outportb(0xA0,0x20); //disable interrupt for upper irq
  outportb(0x20,0x20); //send end-of-interrupt for lower irq
}   // end setflag

/*
******************************************************************************
FUNCTION set_counter()
Purpose: This function performs the setup operations on the 82C54 counter/
	 timer chip.
******************************************************************************
*/
void set_counter(void)
{ inportb(ADDRESS+7);        /* disable  counter functions */
  CtrMode(ADDRESS, 2, 0);    // set counter 2 to mode 0 -- clear reset
  outportb(ADDRESS+7,0);     //enable counters
  inportb(ADDRESS+7);        /* disable  counter functions */
  outportb(ADDRESS+6, 0);    /* Enable Buzzer */
  outportb(ADDRESS+0x0c,0);  /* Select Low clock rate */
  inportb(ADDRESS+0x0D);     /* disable opto reset*/
  inportb(ADDRESS+0x0E);     /* disable opto reset*/
  inportb(ADDRESS+0x0f);     /* disable program outputs*/

  CtrMode(ADDRESS, 0, 3); // set counter 0 to mode 3
  CtrLoad(ADDRESS, 0, 0xFFFF); // load counter 0 with full scale

  CtrMode(ADDRESS, 1, 2); // set counter 1 to mode 2
  CtrLoad(ADDRESS, 1, 0x0010); // load counter 1 with 10 hex

  CtrMode(ADDRESS, 2, 1); // set counter 2 to mode 1
  //CtrLoad(ADDRESS, 2, 0xFFFF);

//Note:Not loading counter 2 creates an infinite reset duration
//Set the reset duration by loading a value in counter 2
//Change counter 2 to mode 2 to set duration
} /* End set_counter() */


/*
******************************************************************************
FUNCTION main()
Purpose: This function controls program flow, making calls to the other
	 functions, and prompting for user input.
******************************************************************************
*/

void main()
{
  unsigned read_back, out_byte;
  int aborted = 0;
  IRQ = 10;
  clrscr();
  ADDRESS=AskForBaseAddress(0xFCA0);
  IRQ=AskForBaseIRQ(IRQ);
  printf("\nPress any key to start.\n");
  getch();


  set_counter();        /* Set counter and start the countdown. */

  inportb(ADDRESS+4);   /* clear any potentially pending IRQs*/
  initirq(IRQ,setflag); //initialize the irq
  outp(ADDRESS+7, 0);   /* Enable counters */

  for (read_back = 0; read_back <=1000; read_back++) {
    CtrMode(ADDRESS, 1, 2); // set counter 1 to mode 2
    CtrLoad(ADDRESS, 1, 0x010); // load counter 1 with 10 hex
    gotoxy(1,8);
    printf("\nUpdating counter 1.  Loop number : %hu", read_back);
    }
  puts("\nWaiting for timeout . . .");

  do {
     aborted=kbhit();
  } while ((byte & 0x1) && (!aborted) && !flag);
  //loop while timeout bit is high, no keypress, and no interrupt
  printf("\n\n%4x",byte);//print inportb(ADDRESS+4) from isr

  restoreirq(IRQ);
  puts("");
  if (aborted) puts("Timeout aborted!"); else
     puts("Watchdog timed out successfully.");
  getch();
  inportb(ADDRESS+7);   //disable counters
  outportb(ADDRESS+5,0);//turn off buzzer
}