//		jan 1, 2000 = day=1, mo=1, year=0

/*
	9*q indexes into the array
char phases[83] =
	"New Moon "
	"Wax Cres "
	"1st Qtr  "
	"Wax Gibb "
	"Full Moon"
	"Wane Gibb"
	"3rd Qtr  "
	"Wane Cres"
	"No Data  ";
*/

unsigned char compute_phase(unsigned char day, unsigned char mo, unsigned char year){
unsigned char q;
unsigned int hi, lo, mid;
unsigned  int probe;


    probe = (unsigned int)day + 31*((unsigned int)mo+(12*(unsigned int)(year)));
	
	if(probe<phase_start[0] || probe >= phase_start[PHASE_DATA_LEN-1]){
		q=7;
	}else{
//		Invariant : phase_start[lo] <= probe < phase_start[hi]
		lo=0; hi= PHASE_DATA_LEN-1;
		while(hi-lo>1){
			mid=lo+( (hi-lo)/2 );
			if(probe < phase_start[mid])	hi=mid;
			else							lo=mid;
		}
		lo+=INITIAL_PHASE;
		lo = lo%8;
		q=lo;
	}
	
	return q;
}