#include <stdio.h>
#include <stdlib.h>
// #include <sys/nearptr.h> // for __djgpp_conventional_base
#include <dpmi.h> // for __dpmi_regs
#include <string.h> // for memset
#include <sys/farptr.h>
#include <go32.h> /* for _dos_ds */
#include <sys/movedata.h> // for dosmemput


// char *scrptr;
char screen_buffer [64000]; // screen is 320x200
__dpmi_regs regs;

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This procedure waits for a key.

void Readkey(void)
{
  memset(&regs, 0, sizeof regs);
  regs.x.ax = 0x01;
  __dpmi_int(0x16, &regs);

}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This procedure gets you into 320x200x256 mode.

void SetMCGA(void)
{
  memset(&regs, 0, sizeof regs);
  regs.x.ax = 0x13;
  __dpmi_int(0x10, &regs);
}
        
//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
//  This procedure returns you to text mode.

void SetText(void)
{
  memset(&regs, 0, sizeof regs);
  regs.x.ax = 0x03;
  __dpmi_int(0x10, &regs);
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This puts a pixel on the screen using interrupts.

void INTPutpixel(unsigned int x,unsigned int y,unsigned char col)
{
  memset(&regs, 0, sizeof regs);
   regs.h.ah=0x0C;
   regs.h.al=col;
   regs.x.bx=0x01;
   regs.x.cx=x;
   regs.x.dx=y;
   __dpmi_int(0x10, &regs);
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This puts a pixel on the screen by writing directly to memory.

void MEMPutpixel(unsigned int x, unsigned int y, unsigned char col)
{
//   *(scrptr + x + y * 320) = col;
_farpokeb(_dos_ds, 0xa0000 + x + y * 320, col);

}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This clears the screen to the specified color

void Cls(unsigned char col)
{
        memset(&screen_buffer, col, 64000);
        dosmemput(screen_buffer,64000,0xa0000);
}


//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This tests out the speed of the MEMPutpixel procedure.
void TestMEMPutpixel(void)
{

  int loop1,loop2;

  for (loop1=0; loop1<=319; loop1++)
  {
    for (loop2=0; loop2<=199; loop2++)
    {
         MEMPutpixel (loop1,loop2,(double)rand () * (256) / RAND_MAX);
    }
  }
  Readkey();
  Cls (0);
}


//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// This tests out the speed of the INTPutpixel procedure.

void TestINTPutpixel(void)
{

  int loop1,loop2;

  for (loop1=0; loop1<=319; loop1++)
  {
    for (loop2=0; loop2<=199; loop2++)
    {
      INTPutpixel (loop1,loop2,(double)rand () * (256) / RAND_MAX);
    }
  }
  Readkey();
  Cls (0);
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// BEGIN Of the main program

int main (void)

{
//   scrptr = (char*) (__djgpp_conventional_base + 0xa0000);
//   __djgpp_nearptr_enable();

  printf ("What will happen is that I will clear the screen twice. After\n");
  printf ("each clear screen you will have to hit a key. I will then fill\n");
  printf ("the screen twice with randomlly colored pixels using two different\n");
  printf ("methoods, after each of which you will have to hit a key. I will\n");
  printf ("then return you to text mode.\n");
  printf ("\n\n");
  printf ("Hit any kay to continue ...\n");
  Readkey();

  SetMCGA();
  Cls (32);
  Readkey();
  Cls (90);

  TestINTPutpixel();

  TestMEMPutpixel();

//  __djgpp_nearptr_disable();

  SetText();


  printf ("All done. This concludes the first sample program in the ASPHYXIA\n");
  printf ("Training series. You may reach DENTHOR under the name of GRANT\n");
  printf ("SMITH on the MailBox BBS, or leave a message to ASPHYXIA on the\n");
  printf ("ASPHYXIA BBS. Get the numbers from Roblist, or write to :\n");
  printf ("             Grant Smith\n");
  printf ("             P.O. Box 270\n");
  printf ("             Kloof\n");
  printf ("             3640\n");
  printf ("I hope to hear from you soon!\n");
  printf ("\n\n");

  printf ("Hit any key to exit ...\n");

  Readkey();
 
  return(0);

} // END Of the main program