#include <stdio.h>
#include <unistd.h> 
#include <sys/io.h>

// Definuje port JOYSTICKu
#define DATA 0x200
#define STATUS DATA
#define CONTROL DATA

float ZmerTo (unsigned short naportu, unsigned char odkud, int stav) 
#define DelkaCyklu  0xffff
{
	int t0, t1, t2;
	int mask = (1 << odkud);
	t1=0;
	t2=0;    
	for (t0 = 0; t0 < DelkaCyklu; t0++) 
		if ((inb (naportu) & mask) == 0) t1++;

	t2=DelkaCyklu-t1;
	if (stav!=0) {
		t1=t2;
		t2=DelkaCyklu-t1;
	};
return ((((double)t2 / ((double)DelkaCyklu)) - 0.318) / 0.0047);
}


int main (void) 
{

	FILE *out_file;
	if (setuid (0) < 0) { 
		printf ("Program musi byt spusten rootem\n"); 
		exit (1); 
	}
	if (ioperm (STATUS, 3, 1)) {
		printf ("Program musi byt spusten rootem\n");
		exit (1);
	}
	if (ioperm (DATA, 4, 1)) {
		printf ("Neni pristup na port\n");
		exit (1);
	}
	
   	// zapis vysledku do souboru
	out_file = fopen("out_file_teplomer","w");
		fprintf(out_file,"%4.1f", ZmerTo (DATA,4, 0));
	fclose(out_file);
return (0);
}