readme.x64
==========

[Note - the gvmat64.asm longest_match routine in Windows 64-bit assembler
and makefile.a64 used to compile it were provided at the last minute and
are currently untested by Info-ZIP.  They are provided to allow testing of
this optimization which is planned for inclusion in Zip 3.0.
USE AT YOUR OWN RISK.  That said, thanks Gilles for providing this
optimization and we plan to better support it in Zip 3.0.  2/28/2005 EG]

makefile.asm64 is a makefile for 64 bits optimized version of zip for 
Microsoft Windows running on AMD64 (Athlon64/Opteron) and Intel EM64T
(the Pentium 4 and Xeon with 64 bits extension)

makefile.asm64 contain a makefile for 64 Microsoft C++ for Windows 64 bits,
extended edition (for both AMD64 and Intel EM64T), included in Visual
Studio 2005

to compile it, start the C++ AMD64 build environnement prompt,
go to the zip source directory and start

   nmake -a -f makefile.a64

This makefile uses gvmat64.asm, which is the optimized longest_match written
in assembly code for AMD64/Intel EM64T

gvmat64.asm was tested by Gilles Vollant on AMD64 with infozip, and also tested
with a lot of file with zLib 1.2.2 on both AMD64 and Intel EM64T processor.

It was written by Gilles Vollant, by modifiying the longest_match
from Jean-loup Gailly in deflate.c of zLib and infoZip zip.
and modifying asm686 (1998), optimised assembly code from Brian Raiter,
(see http://www.muppetlabs.com/~breadbox/software/assembly.html)


Gilles Vollant
info@winimage.com

http://www.winimage.com
http://www.winimage.com/zLibdll