mpz_addmul_ui with ui = 1

[Richard B. Kreckel]

Hi!

Paul Zimmermann wrote:
> an alternate trick is to store in the mpz_t *pointer* a value of the form
> p=2k+1, where k is a small integer. Since pointers are usually even, you
> can easily distinguish between small integers and GMP integers,
> and you obtain the value k = p >> 1. It is also more memory-efficient since
> you don't allocate the mpz_t structure. A famous computer algebra system is
> using that trick together with GMP.
> 
> It might make sense to have another layer on top of mpz with that trick.

Paul, you want to re-implement CLN fixnums and bignums!?!
<http://www.ginac.de/~kreckel/talks/ICMS2006.pdf>, page 8.

;-)
    -richy.
-- 
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>