From 07162fa301835387e4da4278326ec1ff45d1dc3e Mon Sep 17 00:00:00 2001 From: Aki Date: Wed, 29 Sep 2021 21:52:57 +0200 Subject: Squashed 'zlib/' content from commit cacf7f1 git-subtree-dir: zlib git-subtree-split: cacf7f1d4e3d44d871b605da3b647f07d718623f --- contrib/asm686/README.686 | 51 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 contrib/asm686/README.686 (limited to 'contrib/asm686/README.686') diff --git a/contrib/asm686/README.686 b/contrib/asm686/README.686 new file mode 100644 index 0000000..a0bf3be --- /dev/null +++ b/contrib/asm686/README.686 @@ -0,0 +1,51 @@ +This is a patched version of zlib, modified to use +Pentium-Pro-optimized assembly code in the deflation algorithm. The +files changed/added by this patch are: + +README.686 +match.S + +The speedup that this patch provides varies, depending on whether the +compiler used to build the original version of zlib falls afoul of the +PPro's speed traps. My own tests show a speedup of around 10-20% at +the default compression level, and 20-30% using -9, against a version +compiled using gcc 2.7.2.3. Your mileage may vary. + +Note that this code has been tailored for the PPro/PII in particular, +and will not perform particuarly well on a Pentium. + +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 + + +Update: + +I've been ignoring these assembly routines for years, believing that +gcc's generated code had caught up with it sometime around gcc 2.95 +and the major rearchitecting of the Pentium 4. However, I recently +learned that, despite what I believed, this code still has some life +in it. On the Pentium 4 and AMD64 chips, it continues to run about 8% +faster than the code produced by gcc 4.1. + +In acknowledgement of its continuing usefulness, I've altered the +license to match that of the rest of zlib. Share and Enjoy! + +Brian Raiter +breadbox@muppetlabs.com +April, 2007 -- cgit v1.1