#include "xbus.h"
#include <reg51.h>
#include <stdlib.h>

sbit NOSRAM = 0xB0;   /* error pin is P3.0 */
sbit SRAM = 0xB2;   /* noerror pin is P3.2 */
sbit DONE = 0xB3;   /* noerror pin is P3.3 */

void PCReset();
void SRAMTest();
void EndProg ();
void BoxColorCycle();
void DrawBox(int width,int height,int ulx,int uly, unsigned char color);

void main()
{
	PCReset();
	XInit();
	SRAMTest();
	BoxColorCycle();
	EndProg();
}

void PCReset()
{
	IE = 0x00; /* no interrupts */
	P0 = 0xff; /* tristate (not pull down) the port */
	P1 = 0xff; /* tristate (not pull down) the port */
	P2 = 0xff; /* tristate (not pull down) the port */
	P3 = 0xff; /* tristate (not pull down) the port */
}

// Test the 32K of SRAM by writing and reading back
void SRAMTest()
{
	unsigned long errors = 0;
	unsigned char value;
	long address;

	NOSRAM = 0; 
	SRAM = 0;
	DONE = 0;
	for(address=0;address<0x8000;address++)
	{
		value = (unsigned char)address;
		XWrite((unsigned int)address,value);
	}
	for(address=0;address<0x8000;address++)
	{
		value = XRead((unsigned int)address);
		if (value != (unsigned char)address)
		{
			errors++;
		}
	}
	if (errors == 0)
	{
		/* There were no errors in the SRAM */
		SRAM = 1;
	} else {
		/* There were errors in the SRAM */
		NOSRAM = 1;
	}
//	XWrite(0xfff0,(unsigned char)errors);
//	XWrite(0xfff1,(unsigned char)(errors>>8));
//	XWrite(0xfff2,(unsigned char)(errors>>16));
//	XWrite(0xfff3,(unsigned char)(errors>>24));
	DONE = 1;
}

void EndProg ()
{
	while (1) {}
}

void BoxColorCycle()
{
	unsigned char startcolor = 0;
	unsigned char panvalue = 0;
	unsigned int width,height,ulx,uly;
	long address;
	unsigned char value = 0;

	/* this routine was designed for the 512x128 8bit mode */

	/* clear the screen */
	for(address=0;address<0x8000;address++) {
		XWrite((unsigned int)address,value);
	}

	/* draw boxes and color cycle forever */
	/* we don't have access to the color map so we must do */
	/* the color cycling by redrawing with a new color */
	/* only cycle colors 1-63 so background stays black */
	while (1) {
		startcolor++;
		if (startcolor >= 64) {
			startcolor = 1;
			/* assign the next value to the pan register */
			panvalue++;
			if (panvalue > 7) panvalue = 0;
			XWrite(0xffff,panvalue);
		}
    	ulx = (rand()>>5)%240;
     	uly = (rand()>>5)%124;
 		width = (rand()>>5)%240 + 2;
		if (ulx + width > 240) width = 240 - ulx;
		height = (rand()>>5)%120 + 2;
		if (uly + height > 120) height = 120 - uly;
       		DrawBox(width,height,ulx,uly,startcolor);
	}
}

void DrawBox(int width,int height,int ulx,int uly, unsigned char color)
{
	unsigned int x,y,address;

/* this addressing is only for 512xVVVx8bpp */

    	for(y=uly;y<=(uly+height);y++)
      		for(x=ulx;x<=(ulx+width);x++) {
				address = x+(y*256);
				XWrite(address,color);
      	}
}