1999-05-04 21:30:25 +02:00
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This is a patched version of zlib, modified to use
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Pentium-Pro-optimized assembly code in the deflation algorithm. The
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files changed/added by this patch are:
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README.686
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match.S
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The speedup that this patch provides varies, depending on whether the
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compiler used to build the original version of zlib falls afoul of the
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PPro's speed traps. My own tests show a speedup of around 10-20% at
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the default compression level, and 20-30% using -9, against a version
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compiled using gcc 2.7.2.3. Your mileage may vary.
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Note that this code has been tailored for the PPro/PII in particular,
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and will not perform particuarly well on a Pentium.
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If you are using an assembler other than GNU as, you will have to
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translate match.S to use your assembler's syntax. (Have fun.)
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Brian Raiter
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breadbox@muppetlabs.com
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April, 1998
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Added for zlib 1.1.3:
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The patches come from
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http://www.muppetlabs.com/~breadbox/software/assembly.html
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To compile zlib with this asm file, copy match.S to the zlib directory
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then do:
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CFLAGS="-O3 -DASMV" ./configure
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make OBJA=match.o
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2012-03-02 18:15:20 +01:00
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Update:
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I've been ignoring these assembly routines for years, believing that
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gcc's generated code had caught up with it sometime around gcc 2.95
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and the major rearchitecting of the Pentium 4. However, I recently
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learned that, despite what I believed, this code still has some life
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in it. On the Pentium 4 and AMD64 chips, it continues to run about 8%
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faster than the code produced by gcc 4.1.
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In acknowledgement of its continuing usefulness, I've altered the
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license to match that of the rest of zlib. Share and Enjoy!
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Brian Raiter
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breadbox@muppetlabs.com
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April, 2007
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