//-------------------------------------------------------------------
//	vramscan.cpp
//
//	This program should be executed in a terminal window on the 
//	graphical desktop.  It adjusts the CRTC Start-Address value
//	to allow a user to see the entire contents of video memory.
//
//	NOTE: The value of the global variable 'pitch' will need to
//	be modified if the desktop graphics display mode is not set
//	up for truecolor with horizontal resolution of 1280-pixels.  
//
//	  compile using:  $ g++ vramscan.cpp int86.cpp -o vramscan 
//
//	programmer: ALLAN CRUSE
//	written on: 11 OCT 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for lseek() 
#include <sys/io.h>	// for inb(), outl(), etc.
#include "int86.h"	// for init8086(), int86()

#define VENDOR_ID	0x1002	// Advanced Technologies, Inc,
#define DEVICE_ID	0x5B60	// ATI Radeon X300
//#define DEVICE_ID	0x5159	// ATI Radeon 7000
//#define DEVICE_ID	0x5960	// ATI Radeon 9250 Pro

#define CRT_START_ADDR	0x0224
#define CRTC_PITCH	0x022C
#define	MM_INDEX	0
#define MM_DATA		4

unsigned char *vram = (unsigned char*)0xA0000000; 
struct vm86plus_struct	vm; 
int iobase, pitch = 1280*4;


void set_crt_start_address( unsigned int start_address )
{
	outl( CRT_START_ADDR, iobase + MM_INDEX );
	outl( start_address, iobase + MM_DATA ); 
}


int main( int argc, char **argv )
{
	// obtain the port-address for the Radeon engine
	init8086();
	vm.regs.eax = 0xB102;		// PCI Find Device
	vm.regs.ecx = DEVICE_ID;	// Device ID
	vm.regs.edx = VENDOR_ID;	// Vendor ID
	vm.regs.esi = 0x0000;		// device index
	int86( 0x1A, vm );		// invoke BIOS service

	if ( ( vm.regs.eax & 0xFF00 ) == 0 )
		{
		vm.regs.eax = 0xB10A;	// PCI Read Config Dword
		vm.regs.edi = 0x0014;	// register number
		int86( 0x1A, vm );	// invoke BIOS service
		iobase = vm.regs.ecx & ~3;
		fprintf( stderr, "iobase=%04X \n", iobase );
		getchar();
		}
	else	{ fprintf( stderr, "ioport not found\n" ); exit(1); }

	// obtain the size of the installed video memory
	int	vd = open( "/dev/vram", O_RDWR ); 
	if ( vd < 0 ) { perror( "/dev/vram" ); exit(1); }
	int	size = lseek( vd, 0, SEEK_END ); 

	// wait until the user is ready to begin the memory-scan	
	printf( "\nHit <ENTER> to begin scanning video memory\n" );
	getchar();

	// this loop performs a forward scan of video memory
	for (int i = 0; i < size; i+= pitch)
		{
		set_crt_start_address( i );
		while ( (inb( 0x3DA )&8) == 8 );	
		while ( (inb( 0x3DA )&8) == 0 );	
		}
	getchar();

	set_crt_start_address( 0 );	
	printf( "demo is finished\n" );
}