6142ede46f
cosf(x) is supposed to return something like x when x is a NaN, and we actually fairly consistently return x-x which is normally very like x (on i386 and and it is x if x is a quiet NaN and x with the quiet bit set if x is a signaling NaN. Rev.1.10 broke this by normalising x to fabsf(x). It's not clear if fabsf(x) is should preserve x if x is a NaN, but it actually clears the sign bit, and other parts of the code depended on this. The bugs can be fixed by saving x before normalizing it, and using the saved x only for NaNs, and using uint32_t instead of int32_t for ix so that negative NaNs are not misclassified even if fabsf() doesn't clear their sign bit, but gcc pessimizes the saving very well, especially on Athlon XPs (it generates extra loads and stores, and mixes use of the SSE and i387, and this somehow messes up pipelines). Normalizing x is not a very good optimization anyway, so stop doing it. (It adds latency to the FPU pipelines, but in previous versions it helped except for |x| <= 3pi/4 by simplifying the integer pipelines.) Use the same organization as in s_sinf.c and s_tanf.c with some branches reordered. These changes combined recover most of the performance of the unfixed version on A64 but still lose 10% on AXP with gcc-3.4 -O1 but not with gcc-3.3 -O1.
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html