GMP would give speed

[Jean-Luc-Picard-2021]

How are bigints and rationals implemented in Trealla Prolog.
It seems SWI-Prolog uses GMP, which has quite some speed:

/* SWI-Prolog 9.3.22 */
?- time(_ is 8^(8^8)).
% -1 inferences, 0.000 CPU in 0.003 seconds (0% CPU, Infinite Lips)
true.

?- time(_ is 9^(9^9)).
% -1 inferences, 6.078 CPU in 6.399 seconds (95% CPU, 0 Lips)
true.

Mostlikely some Karatsuba multiplication or something, that makes
GMP fast. For Trealla Prolog I get:

/* Trealla Prolog 2.67.24-2 */
?- time(_ is 8^(8^8)).
% Time elapsed 4.685s, 1 Inferences, 0.000 MLips
   true.

?- time(_ is 9^(9^9)).
% hangs and ^C stops working