freebsd kernel with SKQ
011cbae1fe
This uses 2 tricks to improve consistency so that more serious problems aren't hidden in simple regression tests by noise for the NaNs: - for a signaling NaN, adding 0.0 generates the invalid exception and converts to a quiet NaN, and doesn't have too many effects for other types of args (it converts -0 to +0 in some rounding modes, but that hopefully doesn't change the result after adding the NaN arg). This avoids some inconsistencies on i386 and ia64. On these arches, the result of an operation on 2 NaNs is apparently the largest or the smallest of the NaNs as bits (consistently largest or smallest for each arch, but the opposite). I forget which way the comparison goes and if the sign bit affects it. The quiet bit is is handled poorly by not always setting it before the comparision or ignoring it. Thus if one of the args was originally a signaling NaN and the other was originally a quiet NaN, then the result depends too much on whether the signaling NaN has been quieted at this point, which in turn depends on optimizations and promotions. E.g., passing float signaling NaNs to double functions must quiet them on conversion; on i387, loading a signaling NaN of type float or double (but not long double) into a register involves a conversion, so it quiets signaling NaNs, so if the addition has 2 register operands than it only sees quiet NaNs, but if the addition has a memory operand then it sees a signaling NaN iff it is in the memory operand. - subtraction instead of addition is used to avoid a dubious optimization in old versions of gcc. For SSE operations, mixing of NaNs apparently always gives the target operand. This is not as good as the i387 and ia64 behaviour. It doesn't mix NaNs at all, and makes addition not quite commutative. Old versions of gcc sometimes rewrite x+y to y+x and thus give different results (in bits) for NaNs. gcc-3.3.3 rewrites x+y to y+x for one of pow() and powf() but not the other, so starting from float NaN args x and y, powf(x, y) was almost always different from pow(x, y). These tricks won't give consistency of 2-arg float and double functions with long double ones on amd64, since long double ones use the i387 which has different semantics from SSE. Convert to __FBSDID(). |
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| bin | ||
| cddl | ||
| compat/opensolaris | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| ObsoleteFiles.inc | ||
| README | ||
| UPDATING | ||
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 ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. 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. rescue Build system for statically linked /rescue utilities. 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