Description:

This library implements arithmetic and logical operations over
arbitrary-precision integers.

The module is simply named "Z". Its interface is similar to that of the
Int32, Int64 and Nativeint modules from the OCaml standard library, with
some additional functions. See the file z.mlip for documentation.

The implementation uses GMP (the GNU Multiple Precision arithmetic
library) to compute over big integers. However, small integers are
represented as unboxed Caml integers, to save space and improve
performance. Big integers are allocated in the Caml heap, bypassing
GMP's memory management and achieving better GC behavior than e.g. the
MLGMP library. Computations on small integers use a special, faster
path (coded in assembly for some platforms and functions) eschewing
calls to GMP, while computations on large integers use the low-level
MPN functions from GMP.

Arbitrary-precision integers can be compared correctly using OCaml's
polymorphic comparison operators (=, <, >, etc.).

Additional features include:
- a module Q for rationals, built on top of Z (see q.mli)
- a compatibility layer Big_int_Z that implements the same API as Big_int,
but uses Z internally