cpython

History

Stefan Krah ec766a6179 1) Remove claim of an input invariant that is only true for static mpd_t. Resizing is used _inside_ libmpdec functions, and it is permitted to change x->alloc several times while setting x->len at the end of the function. Therefore, for dynamic mpd_t x->alloc can _temporarily_ drop below x->len. Of course the final result always has x->len <= x->alloc. For static mpd_t this cannot happen, since resizing to a smaller coefficient is a no-op. 2) Remove micro optimization in mpd_switch_to_dyn(): Previously only the valid initialized part of the existing coefficient up to x->len was copied to the new dynamic memory area. Now copying does the same as realloc() and the entire old memory area is copied. The rationale for this change is that it is no longer needed to memorize the explanation given in 1).		2012-04-10 23:11:54 +02:00
..
libmpdec	1) Remove claim of an input invariant that is only true for static mpd_t.	2012-04-10 23:11:54 +02:00
tests	Raise InvalidOperation if exponents of zeros are clamped during exact	2012-04-05 15:21:58 +02:00
ISSUES.txt	Issue #7652 : Integrate the decimal floating point libmpdec library to speed	2012-03-21 18:25:23 +01:00
README.txt	Issue #7652 : Integrate the decimal floating point libmpdec library to speed	2012-03-21 18:25:23 +01:00
_decimal.c	Issue #14478 : Cache the hash of a Decimal in the C version.	2012-04-10 16:27:58 +02:00
docstrings.h	Issue #7652 : Integrate the decimal floating point libmpdec library to speed	2012-03-21 18:25:23 +01:00

README.txt


About
=====

_decimal.c is a wrapper for the libmpdec library. libmpdec is a fast C
library for correctly-rounded arbitrary precision decimal floating point
arithmetic. It is a complete implementation of Mike Cowlishaw/IBM's
General Decimal Arithmetic Specification.


Build process for the module
============================

As usual, the build process for _decimal.so is driven by setup.py in the top
level directory. setup.py autodetects the following build configurations:

   1) x64         - 64-bit Python, x86_64 processor (AMD, Intel)

   2) uint128     - 64-bit Python, compiler provides __uint128_t (gcc)

   3) ansi64      - 64-bit Python, ANSI C

   4) ppro        - 32-bit Python, x86 CPU, PentiumPro or later

   5) ansi32      - 32-bit Python, ANSI C

   6) ansi-legacy - 32-bit Python, compiler without uint64_t

   7) universal   - Mac OS only (multi-arch)


It is possible to override autodetection by exporting:

   PYTHON_DECIMAL_WITH_MACHINE=value, where value is one of the above options.


NOTE
====
 
decimal.so is not built from a static libmpdec.a since doing so led to
failures on AIX (user report) and Windows (mixing static and dynamic CRTs
causes locale problems and more).