// ----------------------------------------------------
// Integer and FP sqrt routines,with test driver. 
//
// Copyright 2005,2006, Mike Noel, All Rights Reserved
// ----------------------------------------------------

#include <aCore.tea>
#include <aPrint.tea>
#include "nFP.tea"


#define HowMany 12


// ********************* Integer Routine ********************

int  I_sqrt (int num) {
int i, atest;

	if (num < 0) return (-1);
	for (i=0, atest = num / 2; i<9; i++) {
	    if (atest < 1) return (atest);
	    atest = ((num / atest) + atest) / 2;
	    }
	return (atest);
}      


// ************************ FP Routine **********************

int  FP_sqrt (int num, char exp) {
int newa, olda;
char newax, oldax;

// initial tests for valid input
   if (num < 0)  return (-1);
   if (num == 0) { nFP_mant = 0; return (0); }

// first approx - 1 (one)
   newa = 16384; newax = -14;
   
// successive approx - use new = 0.5 * (old + (num / old))
//   quit when newax = oldax and abs(newa-olda)<10)
//        remember newa and olda are normalize mantissa, 
//        so they are in the range 16k-32k and "<10" means
//        within a 1/10 of a percent...
   do	{
	olda = newa; oldax = newax;
	nFP_reciprocal(olda, oldax);
	if (nFP_error != nFP_err_none) return(-1);
	nFP_multiply(nFP_mant, nFP_exp, num, exp);
	if (nFP_error != nFP_err_none) return(-1);
	nFP_add(nFP_mant, nFP_exp, olda, oldax);
	if (nFP_error != nFP_err_none) return(-1);
	nFP_exp--;	// quick divide by 2...
	newa = nFP_mant; newax = nFP_exp;
   	}
   while ((oldax != newax) || (nFP_intabsval(olda-newa)>10));

   return (newa);
}      


// ******************* Test driver Routine ******************

void main () {
//
int i=0, r=0, s=0;

// Print sign on message
aPrint_String("Test sqrt functions\n");

// Print sign on message
aPrint_String("Test integer sqrt\n");

for (i=0; i<HowMany; i++) {
	r = I_sqrt(i);
	s = r * r;
	aPrint_IntDec(i); aPrint_String("   ");
	aPrint_IntDec(r); aPrint_String("   ");
	aPrint_IntDec(s); aPrint_String("\n");
 	aCore_Sleep(1000);
	}

// Print sign on message
aPrint_String("\nTest floating point sqrt\n");

for (i=0; i<HowMany; i++) {
	aPrint_IntDec(i); aPrint_String("   ");
	aCore_Sleep(1000);
	r = FP_sqrt(i,0);
	if(r<0) {
		aPrint_String("FP error ");
		aPrint_IntDec(nFP_error);
		aPrint_Char('\n');
 		aCore_Sleep(1000);
		}
	else	{
		aPrint_IntDec(nFP_mant); aPrint_String("   ");
		aPrint_IntDec(nFP_exp); aPrint_String("   ");
		aCore_Sleep(1000);
		r = nFP_denormalize();
		if (nFP_error != nFP_err_none) {
			aPrint_String("Denormalize error - ");
 			aCore_Sleep(1000);
			r=0;
			}
		s = r * r;
		aPrint_IntDec(r); aPrint_String("   ");
		aPrint_IntDec(s); aPrint_String("\n");
		}
 	aCore_Sleep(1000);
	}

// Print sign off message
	aPrint_String("Tests finished\n"); 
	aCore_Sleep(1000);
}