BSD 4_1c_2 development

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

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);
}