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-rw-r--r-- | src/boost/tools/boost_install/test/iostreams/zlib-1.2.11/contrib/asm686/README.686 | 51 |
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diff --git a/src/boost/tools/boost_install/test/iostreams/zlib-1.2.11/contrib/asm686/README.686 b/src/boost/tools/boost_install/test/iostreams/zlib-1.2.11/contrib/asm686/README.686 new file mode 100644 index 000000000..a0bf3bea4 --- /dev/null +++ b/src/boost/tools/boost_install/test/iostreams/zlib-1.2.11/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 |