[unix-history] / usr / src / libm / pow.c

/*
	computes a^b.
	uses log and exp
*/

#include	<errno.h>
int errno;
double log(), exp();

double
pow(arg1,arg2)
double arg1, arg2;
{
	double temp;
	long l;

	if(arg1 <= 0.) {
		if(arg1 == 0.) {
			if(arg2 <= 0.)
				goto domain;
			return(0.);
		}
		l = arg2;
		if(l != arg2)
			goto domain;
		temp = exp(arg2 * log(-arg1));
		if(l & 1)
			temp = -temp;
		return(temp);
	}
	return(exp(arg2 * log(arg1)));

domain:
	errno = EDOM;
	return(0.);
}
Commit	Line	Data
5d130d40 RM	1	/*
	2	computes a^b.
	3	uses log and exp
	4	*/
	5
	6	#include <errno.h>
	7	int errno;
	8	double log(), exp();
	9
	10	double
	11	pow(arg1,arg2)
	12	double arg1, arg2;
	13	{
	14	double temp;
	15	long l;
	16
	17	if(arg1 <= 0.) {
	18	if(arg1 == 0.) {
	19	if(arg2 <= 0.)
	20	goto domain;
	21	return(0.);
	22	}
	23	l = arg2;
	24	if(l != arg2)
	25	goto domain;
	26	temp = exp(arg2 * log(-arg1));
	27	if(l & 1)
	28	temp = -temp;
	29	return(temp);
	30	}
	31	return(exp(arg2 * log(arg1)));
	32
	33	domain:
	34	errno = EDOM;
	35	return(0.);
	36	}