update for tahoe

[unix-history] / usr / src / usr.bin / f77 / libF77 / pow_ri.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_ri.c    5.3     %G%
*/

float pow_ri(ap, bp)
float *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;
               }
       if (x == 0)
               return(0);

       for( ; ; )
               {
               if(n & 01)
                       pow *= x;
               if(n >>= 1)
                       x *= x;
               else
                       break;
               }
       }
return(pow);
}