Try our own `ipow()` if both base and exp are fixnums; fix
@@ -52,14 +52,35 @@ static mrb_value
num_pow(mrb_state *mrb, mrb_value x)
{
mrb_value y;
- mrb_float d, yv;
+ mrb_float d;
mrb_get_args(mrb, "o", &y);
- yv = mrb_to_flo(mrb, y);
- d = pow(mrb_to_flo(mrb, x), yv);
- if (mrb_fixnum_p(x) && mrb_fixnum_p(y) && FIXABLE(d) && yv > 0 &&
- (d < 0 || (d > 0 && (mrb_int)d > 0)))
- return mrb_fixnum_value((mrb_int)d);
+ if (mrb_fixnum_p(x) && mrb_fixnum_p(y)) {
+ /* try ipow() */
+ mrb_int base = mrb_fixnum(x);
+ mrb_int exp = mrb_fixnum(y);
+ mrb_int result = 1;
+ mrb_bool ok = TRUE;
+
+ for (;;) {
+ if (exp & 1) {
+ if (mrb_int_mul_overflow(result, base, &result)) {
+ ok = FALSE;
+ break;
+ }
+ }
+ exp >>= 1;
+ if (exp == 0) break;
+ if (mrb_int_mul_overflow(base, base, &base)) {
+ ok = FALSE;
+ break;
+ }
+ }
+ if (ok) {
+ return mrb_fixnum_value(result);
+ }
+ }
+ d = pow(mrb_to_flo(mrb, x), mrb_to_flo(mrb, y));
return mrb_float_value(mrb, d);
}
