//-------------------------------------------------------------------
//	vgascroll.cpp
//
//	This program scrolls through video display memory (using the
//	'write()' capability implemented by our 'sischip.c' module).
//
//	programmer: ALLAN CRUSE
//	date begun: 08 MAY 2003
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for read(), write(), close() 

#define VRES 1024
#define HRES 1280

char filename[] = "/proc/sischip";

int main( int argc, char **argv )
{
	int	sis = open( filename, O_RDWR );
	if ( sis < 0 ) { perror( filename ); exit(1); }
	
	unsigned long	start_address_offset;
	int	nbytes = read( sis, &start_address_offset, 4 );

	printf( "\nnbytes=%d ", nbytes ); 
	printf( " start_address_offset=%08X \n", start_address_offset );

	printf( "\nPress <ENTER> to begin video memory scroll... " );
	getchar();
	
	int	i, j;
	int	maxi = (16<<20)/HRES - VRES;
	int	delay = 2000000;
	unsigned long	where = start_address_offset;
	for (i = 0; i < maxi; i++)
		{
		where += HRES;
		write( sis, &where, 4 );
		for (j = 0; j < delay; j++);
		}
	for (j = 0; j < 100*delay; j++);
	for (i = 0; i < maxi; i++)
		{
		where -= HRES;
		write( sis, &where, 4 );
		for (j = 0; j < delay; j++);
		}
	write( sis, &start_address_offset, 4 );	
}