modulo

/*
 *  call-seq:
 *     flt % other         => float
 *     flt.modulo(other)   => float
 *
 *  Return the modulo after division of <code>flt</code> by <code>other</code>.
 *
 *     6543.21.modulo(137)      #=> 104.21
 *     6543.21.modulo(137.24)   #=> 92.9299999999996
 */

static VALUE
flo_mod(x, y)
    VALUE x, y;
{
    double fy, mod;

    switch (TYPE(y)) {
      case T_FIXNUM:
        fy = (double)FIX2LONG(y);
        break;
      case T_BIGNUM:
        fy = rb_big2dbl(y);
        break;
      case T_FLOAT:
        fy = RFLOAT(y)->value;
        break;
      default:
        return rb_num_coerce_bin(x, y);
    }
    flodivmod(RFLOAT(x)->value, fy, 0, &mod);
    return rb_float_new(mod);
}