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diff --git a/Modules/_decimal/libmpdec/README.txt b/Modules/_decimal/libmpdec/README.txt new file mode 100644 index 0000000000..96b72232d2 --- /dev/null +++ b/Modules/_decimal/libmpdec/README.txt @@ -0,0 +1,90 @@ + + +libmpdec +======== + +libmpdec is a fast C/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. + + +Files required for the Python _decimal module +============================================= + + Core files for small and medium precision arithmetic + ---------------------------------------------------- + + basearith.{c,h} -> Core arithmetic in base 10**9 or 10**19. + bits.h -> Portable detection of least/most significant one-bit. + constants.{c,h} -> Constants that are used in multiple files. + context.c -> Context functions. + io.{c,h} -> Conversions between mpd_t and ASCII strings, + mpd_t formatting (allows UTF-8 fill character). + memory.{c,h} -> Allocation handlers with overflow detection + and functions for switching between static + and dynamic mpd_t. + mpdecimal.{c,h} -> All (quiet) functions of the specification. + typearith.h -> Fast primitives for double word multiplication, + division etc. + + Visual Studio only: + ~~~~~~~~~~~~~~~~~~~ + vccompat.h -> snprintf <==> sprintf_s and similar things. + vcstdint.h -> stdint.h (included in VS 2010 but not in VS 2008). + vcdiv64.asm -> Double word division used in typearith.h. VS 2008 does + not allow inline asm for x64. Also, it does not provide + an intrinsic for double word division. + + Files for bignum arithmetic: + ---------------------------- + + The following files implement the Fast Number Theoretic Transform + used for multiplying coefficients with more than 1024 words (see + mpdecimal.c: _mpd_fntmul()). + + umodarith.h -> Fast low level routines for unsigned modular arithmetic. + numbertheory.{c,h} -> Routines for setting up the Number Theoretic Transform. + difradix2.{c,h} -> Decimation in frequency transform, used as the + "base case" by the following three files: + + fnt.{c,h} -> Transform arrays up to 4096 words. + sixstep.{c,h} -> Transform larger arrays of length 2**n. + fourstep.{c,h} -> Transform larger arrays of length 3 * 2**n. + + convolute.{c,h} -> Fast convolution using one of the three transform + functions. + transpose.{c,h} -> Transpositions needed for the sixstep algorithm. + crt.{c,h} -> Chinese Remainder Theorem: use information from three + transforms modulo three different primes to get the + final result. + + +Pointers to literature, proofs and more +======================================= + + literature/ + ----------- + + REFERENCES.txt -> List of relevant papers. + bignum.txt -> Explanation of the Fast Number Theoretic Transform (FNT). + fnt.py -> Verify constants used in the FNT; Python demo for the + O(N**2) discrete transform. + + matrix-transform.txt -> Proof for the Matrix Fourier Transform used in + fourstep.c. + six-step.txt -> Show that the algorithm used in sixstep.c is + a variant of the Matrix Fourier Transform. + mulmod-64.txt -> Proof for the mulmod64 algorithm from + umodarith.h. + mulmod-ppro.txt -> Proof for the x87 FPU modular multiplication + from umodarith.h. + umodarith.lisp -> ACL2 proofs for many functions from umodarith.h. + + +Library Author +============== + + Stefan Krah <skrah@bytereef.org> + + + |