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author | dkf <donal.k.fellows@manchester.ac.uk> | 2008-12-19 14:44:48 (GMT) |
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committer | dkf <donal.k.fellows@manchester.ac.uk> | 2008-12-19 14:44:48 (GMT) |
commit | 2cd073ec4bf5ea28c2f1d7db65f4ce95cc875611 (patch) | |
tree | 52b7482cbfbaacbd79b4390955254de21b6e7e65 /compat/zlib/contrib/asm586/README.586 | |
parent | bfa6d081abacd1d00e3a459c3d89039849818d6a (diff) | |
download | tcl-2cd073ec4bf5ea28c2f1d7db65f4ce95cc875611.zip tcl-2cd073ec4bf5ea28c2f1d7db65f4ce95cc875611.tar.gz tcl-2cd073ec4bf5ea28c2f1d7db65f4ce95cc875611.tar.bz2 |
Add previously omitted files so we have a complete zlib 1.2.3 distro...
Diffstat (limited to 'compat/zlib/contrib/asm586/README.586')
-rw-r--r-- | compat/zlib/contrib/asm586/README.586 | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/compat/zlib/contrib/asm586/README.586 b/compat/zlib/contrib/asm586/README.586 new file mode 100644 index 0000000..6bb78f3 --- /dev/null +++ b/compat/zlib/contrib/asm586/README.586 @@ -0,0 +1,43 @@ +This is a patched version of zlib modified to use +Pentium-optimized assembly code in the deflation algorithm. The files +changed/added by this patch are: + +README.586 +match.S + +The effectiveness of these modifications is a bit marginal, as the the +program's bottleneck seems to be mostly L1-cache contention, for which +there is no real way to work around without rewriting the basic +algorithm. The speedup on average is around 5-10% (which is generally +less than the amount of variance between subsequent executions). +However, when used at level 9 compression, the cache contention can +drop enough for the assembly version to achieve 10-20% speedup (and +sometimes more, depending on the amount of overall redundancy in the +files). Even here, though, cache contention can still be the limiting +factor, depending on the nature of the program using the zlib library. +This may also mean that better improvements will be seen on a Pentium +with MMX, which suffers much less from L1-cache contention, but I have +not yet verified this. + +Note that this code has been tailored for the Pentium in particular, +and will not perform well on the Pentium Pro (due to the use of a +partial register in the inner loop). + +If you are using an assembler other than GNU as, you will have to +translate match.S to use your assembler's syntax. (Have fun.) + +Brian Raiter +breadbox@muppetlabs.com +April, 1998 + + +Added for zlib 1.1.3: + +The patches come from +http://www.muppetlabs.com/~breadbox/software/assembly.html + +To compile zlib with this asm file, copy match.S to the zlib directory +then do: + +CFLAGS="-O3 -DASMV" ./configure +make OBJA=match.o |