26.5 Arbitrary Precision Integer Support

The efficient support of Arbitrary Precision Integers (”Bignums”) is crucial for a computer algebra system. This version of PSL tries to exploit the given machine hardware as far as possible, e.g. using double size multiplication and division in hardware where available. Because of the different processor architectures the optimal internal representation of bignums may vary between workstations even with same number of bits per word.

The PSL manual mentions the modules “big” and “nbig” which are written in the true spirit of portable software but these are unfortunately not very efficient. We recommend to use the load module zbig instead. In all versions this load module contains the bignum version which we have found to be optimal.