divmod

/*
 *  call-seq:
 *     fix.divmod(numeric)    => array
 *
 *  See <code>Numeric#divmod</code>.
 */
static VALUE
fix_divmod(x, y)
    VALUE x, y;
{
    if (FIXNUM_P(y)) {
        long div, mod;

        fixdivmod(FIX2LONG(x), FIX2LONG(y), &div, &mod);

        return rb_assoc_new(LONG2NUM(div), LONG2NUM(mod));
    }
    return rb_num_coerce_bin(x, y);
}