//-------------------------------------------------------------------
//	vesainfo.cpp
//
//	This program uses the Linux 'vm86()' system-call to execute 
//	some SVGA firmware procedures (supplied by the manufacturer 
//	of any VESA-compliant video display controller) which offer
//	information about the capabilities of your graphics system;
//	in particular, a list of the supported VESA graphics modes.
//
//	  compile with:  $ g++ vesainfo.cpp int86.cpp -o vesainfo
//
//	Reference: 
//	"VESA BIOS Extension (VBE) Core Functions Standard, version
//	3.0", Video Electronics Standards Association (1998).
//
//	programmer: ALLAN CRUSE
//	written on: 10 JUN 2005
//	revised on: 29 AUG 2005
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <unistd.h>	// for gethostname()  
#include <stdlib.h>	// for exit() 
#include <string.h>	// for strncpy()
#include "int86.h"	// for init8086(), int86()

typedef struct 	{
		unsigned char	VbeSignature[4];
		unsigned char	VbeVersion[2];
		unsigned short	OemStringPtr[2];
		unsigned char	Capabilities[4];
		unsigned short	VideoModePtr[2];
		unsigned short	TotalMemory;
		unsigned char	OemSoftwareRev[2];
		unsigned short	OemVendorNamePtr[2];
		unsigned short	OemProductNamePtr[2];
		unsigned char	Reserved[222];
		unsigned char	OemData[256];
		} VbeInfoBlk;

typedef struct	{
		unsigned short	ModeAttributes;
		unsigned char	WinAAttributes;
		unsigned char	WinBAttributes;
		unsigned short	WinGranularity;
		unsigned short	WinSize;
		unsigned short	WinASegment;
		unsigned short	WinBSegment;
		unsigned short	WinFuncPtr[2];
		unsigned short	BytesPerScanLine;
		unsigned short	XResolution;
		unsigned short	YResolution;
		unsigned char	XCharSize;
		unsigned char	YCharSize;
		unsigned char	NumberOfPlanes;
		unsigned char	BitsPerPixel;
		unsigned char	NumberOfBanks;
		unsigned char	MemoryModel;
		unsigned char	BankSize;
		unsigned char	NumberOfImagePages;
		unsigned char	Reserved;
		unsigned char	RedMaskSize;
		unsigned char	RedFieldPosition;
		unsigned char	GreenMaskSize;
		unsigned char	GreenFieldPosition;
		unsigned char	BlueMaskSize;
		unsigned char	BlueFieldPosition;
		unsigned char	RsvdMaskSize;
		unsigned char	RsvdFieldPosition;
		unsigned char	DirectColorModeInfo;
		unsigned long	PhysBasePtr;	
		unsigned long	Reserved1;
		unsigned short	Reserved2;
		unsigned short	LinBytesPerScanLine;
		unsigned char	BnkNumberOfImagePages;
		unsigned char	LinNumberOfImagePages;
		unsigned char	LinRedMaskSize;
		unsigned char	LinRedFieldPosition;
		unsigned char	LinGreenMaskSize;
		unsigned char	LinGreenFieldPosition;
		unsigned char	LinBlueMaskSize;
		unsigned char	LinBlueFieldPosition;
		unsigned char	LinRsvdMaskSize;
		unsigned char	LinRsvdFieldPosition;
		unsigned long	MaxPixelClock;
		unsigned char	Reserved3[189];
		} ModeInfoBlock;

struct vm86plus_struct	vm;

int main( int argc, char **argv )
{
	// get the hostname for this workstation (will identify output)
	char	hostname[ 64 ] = "";
	gethostname( hostname, 64 );

	//-------------------------------------------------------------
	// Here we execute VESA BIOS function 0.
	//
	//	expects:	AX = 4F00h
	//			ES:DI = address for information block
	//			(initial dword is 'VBE2' if 512 butes)
	//
	//	returns:	AX = 004F (success) or 014F (failure)
	//-------------------------------------------------------------
	init8086();	// setup simulated 8086 execution environment
	VbeInfoBlk	*vbe = (VbeInfoBlk*)0x00010000;
	strncpy( (char*)vbe, "VBE2", 4 ); // plant the signature
	vm.regs.eax = 0x4F00;	// VESA 'Get VbeInfoBlk' service
	vm.regs.es  = 0x1000;	// segment-address for structure
	vm.regs.edi = 0x0000; 	// offset-address for structure
	int86( 0x10, vm );	// execute software interrupt 
	if ( vm.regs.eax != 0x004F )
		{ fprintf( stderr, "VbeInfoBlk not found\n" ); exit(1); }

	unsigned char	*cp;
	unsigned short	*wp; 
	printf( "\n\nVESA BIOS Extensions Information\n\n" );
	printf( "\tVbeSignature: %s \n", vbe->VbeSignature );
	cp = vbe->VbeVersion;
	printf( "\tVbeVersion: %d.%d \n", cp[1], cp[0] );
	wp = (unsigned short*)vbe->OemStringPtr;
	printf( "\tOemStringPtr: %04X:%04X   ", wp[1], wp[0] );
	cp = (unsigned char*)( 16L * wp[1] + wp[0] );
	printf( "\'%s\' \n", cp );
	cp = (unsigned char *)vbe->Capabilities;
	printf( "\tCapabilities: " );
	for (int i = 0; i < 4; i++) printf( "%02X ", cp[i] );	
	printf( "\n" );
	wp = vbe->VideoModePtr;
	printf( "\tVideoModePtr: %04X:%04X \n", wp[1], wp[0] );
	printf( "\tTotalMemory: %d KB \n", vbe->TotalMemory * 64 );
	cp = vbe->OemSoftwareRev;
	printf( "\tOemSoftwareRev: %d.%d \n", cp[1], cp[0] );
	wp = vbe->OemVendorNamePtr;
	printf( "\tOemVendorNamePtr: %04X:%04X   ", wp[1], wp[0] );
	cp = (unsigned char*)( 16L * wp[1] + wp[0] );
	printf( "\'%s\' \n", cp );
	wp = vbe->OemProductNamePtr;
	printf( "\tOemProductNamePtr: %04X:%04X   ", wp[1], wp[0] );
	cp = (unsigned char*)( 16L * wp[1] + wp[0] );
	printf( "\'%s\' \n", cp );

	printf( "\nList of VESA video modes supported " );
	printf( "on workstation \'%s\': \n", hostname );
	wp = (unsigned short *)vbe->VideoModePtr;
	short	*vp = (short*)( 16L * wp[1] + wp[0] );
	int	nmodes;		// number of supported modes
	for (nmodes = 0; nmodes < 64; nmodes++)
		{
		if ( vp[ nmodes ] == ~0 ) break;
		if ( ( nmodes % 12 ) == 0 ) printf( "\n   " );
		printf( " %04X ", vp[ nmodes ] );
		}
	printf( "\n" );

	//-------------------------------------------------------------
	// Here we repeatedly execute VESA BIOS function 1.
	//
	//	expects:	AX = 4F01h
	//			BX = vesa mode-number
	//			ES:DI = address for information block
	//
	//	returns:	AX = 004F (success) or 014F (failure)
	//-------------------------------------------------------------
	ModeInfoBlock	*mi;
	for (int i = 0; i < nmodes; i++)
		{
		mi = (ModeInfoBlock*)(0x00010200 + 256*i);
		memset( (void*)mi, 0x00, 256 );

		vm.regs.eax = 0x4F01;	// VESA 'Get ModeInfoBlk' 
		vm.regs.ecx = vp[i];	// which vesa mode-number 
		vm.regs.es  = 0x1000;	   // segment-address for info
		vm.regs.edi = 512 + 256*i; // offset-address for info
		int86( 0x10, vm );	// execute software interrupt

		printf( "\nmode 0x%04X: ", vp[i] );
		printf( "%2d-bpp ", mi->BitsPerPixel );
		printf( "%4dx%-4d ", mi->XResolution, mi->YResolution );
		printf( "MemoryModel=%d ", mi->MemoryModel );
		printf( "NumberOfPlanes=%d ", mi->NumberOfPlanes );
		if ( mi->ModeAttributes & (1<<3) ) printf( "color " );
		else	printf( "monochrome " );
		if ( mi->ModeAttributes & (1<<4) ) printf( "graphics " );
		else	printf( "text " );
		}
	printf( "\n\n" );
}