//-------------------------------------------------------------------
//	romfonts.cpp
//
//	This program uses the Linux Real Mode Interface to execute
//	a routine in the VIDEO ROM BIOS that returns the real-mode
//	memory address for each built-in character glyph table.
//
//	compile using:	root# g++ romfonts.cpp lrmi.o -o romfonts
//	execute using:  root# ./romfonts
//
//	NOTE: This program must be executed with root privileges.
//
//	programmer: ALLAN CRUSE
//	written on: 09 SEP 2003
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <stdlib.h>	// for exit() 
#include <sys/io.h>	// for iopl()

// for C++ these function prototypes need to preceed the lrmi.h header
extern "C" int LRMI_init( void );
extern "C" int LRMI_int( int, struct LRMI_regs * );
#include "lrmi.h"	// for LRMI_init(), LRMI_int()


void get_font_info( struct LRMI_regs *r, int which ) 
{
	r->eax = 0x1130;	// character generator interface: find font
	r->ebx = which << 8;	// the subfunction-ID goes into register BH
	if ( !LRMI_int( 0x10, r ) )
		fprintf( stderr, "Cannot find font address\n" );
}

char *legend[ 8 ] = { "", "", "8x14 font (0x00-0xFF)", "8x8 font (0x00-0x7F)", 
			"8x8 font (0x80-0xFF)", "9x14 font (alternates)", 
			"8x16 font (0x00-0xFF)", "9x16 font (alternates)" };

int main( void )
{
	if ( iopl( 3 ) ) { perror( "iopl" ); exit(1); }
	if ( !LRMI_init() ) { perror( "LRMI_init" ); exit(1); }

	printf( "\nReal-mode addresses for the built-in character-tables\n" );
	struct LRMI_regs  r = {0};
	int	i = 2;
	do	{
		get_font_info( &r, i );
		printf( "\n\t%04X:%04X ", r.es, r.ebp );
		printf( " %s ", legend[ i ] );
		}
	while ( ++i < 8 );
	printf( "\n\n" );
}