//-------------------------------------------------------------------
//	mmiodiff.cpp
//
//	This user-space application uses the 'read()' and 'llseek()'
//	functions provided within our '82573.c' device-driver module 
//	to investigate a claim that Intel's Pro1000 gigabit ethernet
//	controller implements the same i/o-memory register-values at
//	two different locations (although this fact is not disclosed
//	in the official Intel programming reference manual); namely,
//	the 128-byte i/o-memory range 0x05400-0x0547F which is named
//	the 'Receive-address Array' in Intel's manual can apparently 
//	be accessed at the alternate i/o-memory range 0x00040-000BF.
//
//		compile using:  $ g++ mmiodiff.cpp -o mmiodiff
//		execute using:  $ ./mmiodiff
//
//	NOTE: This application requires our '82573.c' device-driver.
//
//	programmer: ALLAN CRUSE
//	written on: 19 FEB 2008
//-------------------------------------------------------------------

#include <stdio.h>	// for printf(), perror() 
#include <fcntl.h>	// for open() 
#include <stdlib.h>	// for exit() 
#include <unistd.h>	// for lseek(), read()

#define RANGE_SIZE	0x80		// 128-byte i/o address-range
#define NUM_REGS    (RANGE_SIZE >> 2)	// number of 32-bit registers

char	devname[] = "/dev/82573";	// our device-file's pathname

int main( int argc, char **argv )
{
	// open the device-file for reading
	int	fd = open( devname, O_RDONLY );
	if ( fd < 0 ) { perror( devname ); exit(1); }

	// read register-range 0x05400-0x0547F into a local array
	unsigned int  range1[ NUM_REGS ];
	lseek( fd, 0x05400, SEEK_SET );
	for (int i = 0; i < NUM_REGS; i++) read( fd, &range1[i], 4 );

	// read register-range 0x00040-0x000BF into a local array
	unsigned int  range2[ NUM_REGS ];
	lseek( fd, 0x00040, SEEK_SET );
	for (int i = 0; i < NUM_REGS; i++) read( fd, &range2[i], 4 );

	// count the number of mismatched register-entries (if any)
	int	mismatch = 0;
	for (int i = 0; i < NUM_REGS; i++)
		{
		printf( "\n 0x%04X: ", 4*i );
		printf( " %08X ", range1[ i ] );
		printf( " %08X ", range2[ i ] );
		if ( range1[ i ] != range2[ i ] ) ++mismatch;
		}
	printf( "\n\n Number of mismatched entries: %d \n\n", mismatch );
}