source: lmdz_wrf/WRFV3/external/io_grib1/WGRIB/intpower.c @ 1

#include <stdio.h>
#include <stdlib.h>

/*
 * w. ebisuzaki
 *
 *  return x**y
 *
 *
 *  input: double x
 *         int y
 */
double int_power(double x, int y) {

        double value;

        if (y < 0) {
                y = -y;
                x = 1.0 / x;
        }
        value = 1.0;

        while (y) {
                if (y & 1) {
                        value *= x;
                }
                x = x * x;
                y >>= 1;
        }
        return value;
}