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| Name | Date | Size | |
|---|---|---|---|
| match.S | 28-Mar-2012 | 10.6K | |
| README.586 | 28-Mar-2012 | 1.6K | |
README.586
1 This is a patched version of zlib modified to use 2 Pentium-optimized assembly code in the deflation algorithm. The files 3 changed/added by this patch are: 4 5 README.586 6 match.S 7 8 The effectiveness of these modifications is a bit marginal, as the the 9 program's bottleneck seems to be mostly L1-cache contention, for which 10 there is no real way to work around without rewriting the basic 11 algorithm. The speedup on average is around 5-10% (which is generally 12 less than the amount of variance between subsequent executions). 13 However, when used at level 9 compression, the cache contention can 14 drop enough for the assembly version to achieve 10-20% speedup (and 15 sometimes more, depending on the amount of overall redundancy in the 16 files). Even here, though, cache contention can still be the limiting 17 factor, depending on the nature of the program using the zlib library. 18 This may also mean that better improvements will be seen on a Pentium 19 with MMX, which suffers much less from L1-cache contention, but I have 20 not yet verified this. 21 22 Note that this code has been tailored for the Pentium in particular, 23 and will not perform well on the Pentium Pro (due to the use of a 24 partial register in the inner loop). 25 26 If you are using an assembler other than GNU as, you will have to 27 translate match.S to use your assembler's syntax. (Have fun.) 28 29 Brian Raiter 30 breadbox (a] muppetlabs.com 31 April, 1998 32 33 34 Added for zlib 1.1.3: 35 36 The patches come from 37 http://www.muppetlabs.com/~breadbox/software/assembly.html 38 39 To compile zlib with this asm file, copy match.S to the zlib directory 40 then do: 41 42 CFLAGS="-O3 -DASMV" ./configure 43 make OBJA=match.o 44
