How to compile GNU MPFR with mini-gmp
=====================================

To build and test MPFR against mini-gmp:

  ./configure --with-mini-gmp=DIR [other configure options]
  make
  make check

where DIR is the directory that contains mini-gmp
(for example .../gmp-6.2.0/mini-gmp).

"make" will build mini-gmp with the same compiler as for MPFR.

For "make check", tests that use features not supported by mini-gmp
(mpq_t, mpf_t, and the gmp_*printf functions) are skipped.

Note: To use this version of the MPFR library, you need to define
the MPFR_USE_MINI_GMP macro before including mpfr.h (alternatively,
you can modify mpfr.h to define this macro at the beginning, though
this is discouraged). And since mini-gmp currently does not provide
random functions, you also need to define the gmp_randstate_t type
with

  typedef long int gmp_randstate_t[1];

before including mpfr.h (or you may want to modify mini-gmp.h).

Remark: The random functions provided by MPFR configured with mini-gmp
use the standard rand() function, thus one should avoid mini-gmp if one
needs some really serious random functions. Another consequence is that
these functions may not be thread-safe.

The build with mini-gmp may require ISO C99+ features, such as "long long".

This was tested with MPFR svn r13974 and GMP 6.2.0 on x86_64 GNU/Linux:
============================================================================
Testsuite summary for MPFR 4.1.0-dev
============================================================================
# TOTAL: 183
# PASS:  172
# SKIP:  11
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0
============================================================================

How to use mini-gmp with reduced limb size
==========================================

Following the idea of Micro-GMP [1], the GMP developers have adapted mini-gmp
so that it can be used with a reduced limb size. For that, you need GMP 6.2.0
(or later) and define the MINI_GMP_LIMB_TYPE macro with the associated base
type, e.g.

  -DMINI_GMP_LIMB_TYPE=char   (in practice, 8 bits)
  -DMINI_GMP_LIMB_TYPE=short  (in practice, 16 bits)
  -DMINI_GMP_LIMB_TYPE=int    (in practice, 32 bits)

For example:

  ./configure --with-mini-gmp=DIR CFLAGS="-DMINI_GMP_LIMB_TYPE=int"

This was tested with MPFR svn r13974 and GMP 6.2.0 on x86_64 GNU/Linux:
============================================================================
Testsuite summary for MPFR 4.1.0-dev
============================================================================
# TOTAL: 183
# PASS:  172
# SKIP:  11
# XFAIL: 0
# FAIL:  0
# XPASS: 0
# ERROR: 0
============================================================================

[1] https://members.loria.fr/PZimmermann/talks/microgmp.pdf