#include <stdio.h>
#include <stdlib.h> // for the rand() function


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

void Readkey(void)
{
        #pragma aux Readkey =   \
        "mov ax, 0001h",        \
        "int 16h"               \
        modify [ax];
}


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

void SetMCGA(void)
{
        #pragma aux SetMCGA =   \
        "mov ax, 0013h",        \
        "int 10h"               \
        modify [ax];
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
//  This procedure returns you to text mode.

void SetText(void)
{
        #pragma aux SetText =   \
        "mov ax, 0003h",        \
        "int 10h"               \
        modify [ax];
}

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

void INTPutpixel (unsigned int x, unsigned int y, unsigned char col)
{

        #pragma aux INTPutpixel =       \
        "mov ah, 0Ch",                  \
        "mov bx, [1]"                   \
        "int 10h",                      \
        parm [cx] [dx] [al]             \
        modify [ax bx cx dx];
}

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

void MEMPutpixel(unsigned int x, unsigned int y, unsigned char col)
{
        *((char*) 0xa0000 + (y*320) + x) = col;
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// 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,(int) 256 * rand() / 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,(int) 256 * rand() / RAND_MAX );
    }
  }
  Readkey();
  Cls (0);
}

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

void Cls(unsigned char col)
{
        memset((char*) 0xa0000, col, 64000);
}

//ִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִִ
// BEGIN Of the main program

int main (void)

{

//  clrscr();               // This clears the text Screen
  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);
  Readkey();
  TestINTPutpixel();
  TestMEMPutpixel();
  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