#include <stdio.h>
#include <atari.h>
#include <_atarios.h>

void draw_board()
{
	register unsigned char i1b, i2b, i3b, x, modLine;
	register unsigned char *screen = OS.savmsc;
	modLine = 0;

	for (i3b = 1; i3b <= 8; ++i3b)
	{
		for (i2b = 1; i2b <= 24; ++i2b)
		{
			x = 0;
			for (i1b = 1; i1b <= 8; ++i1b)
			{
				if ((i1b & 1) != modLine)
				{
					screen[x] = 255;
					screen[x + 1] = 255;
					screen[x + 2] = 255;
				}
				x += 3;
			}
			screen += 40;
		}
		if ((i3b & 1) == 0)
			modLine = 0;
		else
			modLine = 1;
	}
}

void main(void)
{
	unsigned char stop;
	unsigned char I;

	_graphics(8 + 16);
	OS.color1 = 1;
	OS.color2 = 11;
	OS.color4 = 12;
	OS.rtclok[2] = 0;
	while (OS.rtclok[2] < 150)
	{
		draw_board();
		++I;
	}
	stop = OS.rtclok[2];
	_graphics(0);
	printf("%u", I);
	infinite:
		goto infinite;
}