[unix-history] / usr / src / usr.bin / f77 / libF77 / pow_di.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *	@(#)pow_di.c	5.1	%G%
 */

double pow_di(ap, bp)
double *ap;
long int *bp;
{
double pow, x;
long int n;

pow = 1;
x = *ap;
n = *bp;

if(n != 0)
	{
	if(n < 0)
		{
		if(x == 0)
			{
			return(pow);
			}
		n = -n;
		x = 1/x;
		}
	for( ; ; )
		{
		if(n & 01)
			pow *= x;
		if(n >>= 1)
			x *= x;
		else
			break;
		}
	}
return(pow);
}
Commit	Line	Data
69fcff2c	1	/*
989888af RE	2	* Copyright (c) 1980 Regents of the University of California.
	3	* All rights reserved. The Berkeley software License Agreement
	4	* specifies the terms and conditions for redistribution.
	5	*
	6	* @(#)pow_di.c 5.1 %G%
69fcff2c DW	7	*/
	8
	9	double pow_di(ap, bp)
	10	double *ap;
	11	long int *bp;
	12	{
	13	double pow, x;
	14	long int n;
	15
	16	pow = 1;
	17	x = *ap;
	18	n = *bp;
	19
	20	if(n != 0)
	21	{
	22	if(n < 0)
	23	{
	24	if(x == 0)
	25	{
	26	return(pow);
	27	}
	28	n = -n;
	29	x = 1/x;
	30	}
	31	for( ; ; )
	32	{
	33	if(n & 01)
	34	pow *= x;
	35	if(n >>= 1)
	36	x *= x;
	37	else
	38	break;
	39	}
	40	}
	41	return(pow);
	42	}