//-------------------------------------------------------------------
//	dactable.cpp
//
//	This program illustrates direct I/O programming of the VGA's
//	hardware registers: specifically, it inputs values currently
//	stored in the Digital-to-Analog Converter's color registers,
//	and then displays those values as hexadecimal R-G-B triples.
//
//		      compile using:  $ make dacinput
//
//	NOTE: You should execute 'iopl3' before launching this demo.
//
//	programmer: ALLAN CRUSE
//	written on: 30 AUG 2005
//-------------------------------------------------------------------

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

int main( int argc, char **argv )
{
	// set this task's I/O Privilege-Level to 3
	if ( iopl( 3 ) ) { perror( "iopl" ); exit(1); }

	// read the 256 DAC color registers
	unsigned char	dac[ 768 ];
	outb( 0x00, 0x03C7 );	// initialize DAC Pixel Index for reading

	// input the (r,g,b) components for 256 color registers
	for (int i = 0; i < 768; i++) dac[ i ] = inb( 0x3C9 );	
	
	// display the color-registers as hexadecimal triples
	printf( "\n\tContents of the DAC Color-Table Registers: \n" );
	for (int i = 0; i < 256; i++)
		{
		if ( ( i % 4 ) == 0 ) printf( "\n\t" );
		printf( " %3d: ", i );
		printf( "%02X-", dac[ 3*i + 0 ] );
		printf( "%02X-", dac[ 3*i + 1 ] );
		printf( "%02X ", dac[ 3*i + 2 ] );
		}
	printf( "\n\n" );
}