multi precision arithmetic

[Marc Ernst Eddy van Woerkom]

Hi list,

I have a task which involves writing a small arithmetics lib
(+ - * / < = >) that should be able to calculate exact results
for a given number of digits behind the radix point and is
able to handle digits from different (integer) bases.

Correctness is more important than speed or efficient memory
usage.

To my big surprise I found no existing lib or package so far 
that meets these requirements. (See references for what I looked
at) In some cases I was not really sure, because I had trouble 
to understand the available docs.

The existing software has a strong bias on efficiency or 
efficent memory usage (to handle as large numbers as possible).
Most applications seem to be from cryptology or algorithmic
number theory. 

Another surprise was to find such software included in the web 
scripting language PHP, obviously I paid no close attention to 
the term "base64 encoding" :)

One of systems I had a quick look at was Erlang, because
of the example of calculation n! with obvious more than
standard precision in the introduction.

The specs

  http://www.erlang.org/download/erl_spec47.ps.gz

tell me that what I look for is a bignum.

Where can I find some docs on what is implemented in the
present Erlang/OTP releases?

Regards,
Marc


References
----------

[Bernstein] 
  http://cr.yp.to/papers/m3.dvi

[BigNum]
  http://www.mit.edu/afs/athena.mit.edu/contrib/bignum

[FreeBSD Ports]
  http://www.freebsd.org/ports/math.html

[GNU MP]
  http://www.swox.com/gmp

[Google]
  http://www.google.com

[Howell]
  http://www.cis.ksu.edu/~howell/calculator/calc.html

[Knuth] 
  Knuth, Vol. 2, Kapitel 4

[LiDIA]
  http://www.informatik.tu-darmstadt.de/TI/LiDIA

[LiDIA 2]
  http://www.math.psu.edu/local_doc/LiDIA/node25.html

[Maple]
  http://www.maplesoft.com

[MuPAD]
  http://www.mupad.de

[Octave]
  http://www.octave.org

[PARI-GP]
  http://www.math.u-psud.fr/~belabas/pari.html

[Zheng] 
  http://www.math.uwaterloo.ca/~wwzheng/62/62.html

[Zimmermann] 
  http://www.loria.fr/~zimmerma/bignum/compnew.ps.gz

[Zimmermann2] 
  http://www.loria.fr/~zimmerma/bignum