//-------------------------------------------------------------------
//	horizpan.cpp
//
//	This program shows how to implement horizontal panning over
//	an image in video memory whose width is eight screens wide, 
//	using the ATI Radeon's CRTC_PITCH and CRTC_START registers.
//	
//	  compile using:  $ g++ horizpan.cpp int86.cpp -o horizpan 
//
//	programmer: ALLAN CRUSE
//	written on: 01 NOV 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for read(), write(), close() 
#include <sys/mman.h>	// for mmap() 
#include <sys/io.h>	// for inb(), outb(), 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 CRTC_START	0x0224	// Start-Address register
#define CRTC_PITCH	0x022C	// Scanline-Width register

unsigned char *vram = (unsigned char*)0xA0000000; 
int vesa_mode = 0x4107, hres = 1280, vres = 1024;
int iobase, pitch = hres*8;
struct vm86plus_struct	vm; 

int main( int argc, char **argv )
{
	// obtain the Radeon engine's i/o port-address
	init8086();
	vm.regs.eax = 0xB102;		// PCI Find Device
	vm.regs.ecx = DEVICE_ID;
	vm.regs.edx = VENDOR_ID;
	vm.regs.esi = 0;
	int86( 0x1A, vm );
	if ( ( vm.regs.eax & 0xFF00 ) == 0 )
		{
		vm.regs.eax = 0xB10A;	// PCI Read Config Dword
		vm.regs.edi = 0x0014;	// address of resource 1
		int86( 0x1A, vm );
		iobase = vm.regs.ecx & ~3;
		printf( "\nRadeon i/o port: %04X \n", iobase );
		getchar();
		}
	else	{
		fprintf( stderr, "Radeon device not detected\n" );
		exit(1);
		}		

	// memory-map the display-memory into user-space
	int	vd = open( "/dev/vram", O_RDWR ); 
	if ( vd < 0 ) { perror( "/dev/vram" ); exit(1); }
	int	size = lseek( vd, 0, SEEK_END ); 
	int	prot = PROT_READ | PROT_WRITE; 
	int	flag = MAP_FIXED | MAP_SHARED; 
	if ( mmap( (void*)vram, size, prot, flag, vd, 0 ) == MAP_FAILED )
		{ perror( "mmap" ); exit(1); } 
	
	// enter graphics mode 
	vm.regs.eax = 0x4F02;	
	vm.regs.ebx = vesa_mode;	
	int86( 0x10, vm );	
	
	// set pitch for wide view
	outl( CRTC_PITCH, iobase + 0 );
	outl( 8*inl( iobase + 4 ), iobase + 4 );

	// draw widescreen border 
	int	x = 0, y = 0, color = 15; 
	do { vram[ y * pitch + x ] = color; ++x; } while ( x < pitch-1 ); 
	do { vram[ y * pitch + x ] = color; ++y; } while ( y < vres-1 ); 
	do { vram[ y * pitch + x ] = color; --x; } while ( x >      0 ); 
	do { vram[ y * pitch + x ] = color; --y; } while ( y >      0 ); 
	getchar();

	// color differently some upper scanlines on the eight pages
	for (int i = 0; i < 8; i++)
		{
		unsigned char	*dstn = vram + i*hres;
		int		color = 33 + i;
		for (int y = 2; y < vres/6; y++)
			for( int x = 2; x < hres-2; x++)
				dstn[ y * pitch + x ] = color;
		}
	getchar();

	// main loop to do the horizontal panning
	int	step_size = pitch / 64;
	int	num_steps = 64;
	for (int i = 1; i < num_steps; i++)
		{
		int	crtc_start = i * step_size;
		outl( CRTC_START, iobase + 0 ); 
		outl( crtc_start, iobase + 4 );
		getchar();
		}

	// leave graphics mode 
	vm.regs.eax = 0x0003;	
	int86( 0x10, vm );	
	printf( "\n" );
}