#include <stdio.h>
#include <i86.h>
#include <conio.h>
#include <dos.h>

extern void __cdecl enableUnchainedVGAMode();
extern void __cdecl enableTextMode();
extern void __cdecl fillScreen(int);
extern void __cdecl latchCopyCube(
  char offset,
  int writtenValue,
  int writeMode,
  int setResetRegister,
  int enableSetResetRegister
);
extern void __cdecl writeCube(
  char offset,
  int writeMode,
  int setResetRegister,
  int enableSetResetRegister
);
extern void __cdecl drawColorCube(
  char offset,
  int color
);
extern int __cdecl paramTest(int wow);

extern void far interrupt keyboardHandler();
extern char keyboardPressed;
extern char lastScancode;

char far *VGA = (char*)0xA0000;

#define PLANE_WIDTH (320 / 4)

void far (interrupt *int9Save)();

void populateExampleCube(void) {
  int y, x;

  outp(0x3c4, 0x02);

  for (y = 0; y < 16; ++y) {
    for (x = 0; x < 16; ++x) {
      outp(0x3c5, 1 << (x % 4));
      VGA[y * PLANE_WIDTH + x / 4] = y * 16 + x;
    }
  }
}

int main(void) {
  // activate unchained vga mode
  // set up 8 very clear colors
  // place some data into video memory to be latch copied
  // show off the following
  // * latch copies
  // * masking
  // * barrel shifting

  int i,j;

  int9Save = _dos_getvect(9);
  _dos_setvect(9, keyboardHandler);

  enableUnchainedVGAMode();

  outp(0x3c8, 255);
  outp(0x3c9, 63);
  outp(0x3c9, 63);
  outp(0x3c9, 63);

  fillScreen(0);

  /*
  populateExampleCube();
  latchCopyCube(8, 0, 0x00, 0, 0);
  latchCopyCube(12, 127, 0x00, 0, 0);
  latchCopyCube(16, 0, 0x08, 0, 0);
  latchCopyCube(20, 127, 0x08, 0, 0);
  latchCopyCube(24, 0, 0x10, 0, 0);
  latchCopyCube(28, 127, 0x10, 0, 0);
  latchCopyCube(32, 0, 0x18, 0, 0);
  latchCopyCube(36, 127, 0x18, 0, 0);
  latchCopyCube(40, 0, 0x18 + 0x04, 0, 0);
  latchCopyCube(44, 127, 0x18 + 0x04, 0, 0);
  latchCopyCube(64, 0, 0x10, 7, 7);
  latchCopyCube(68, 0, 0x10, 7, 0);
  latchCopyCube(72, 0, 0x10, 0, 7);
  */

  writeCube(0, 0x10, 0, 0);
  writeCube(4, 0x10, 7, 0);
  writeCube(8, 0x10, 7, 7);
  writeCube(12, 0x10, 0, 7);

  while (keyboardPressed == 0);

  _dos_setvect(9, int9Save);

  enableTextMode();

  return 0;
}