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J.H. van de Water 4c4c19f548 Keep the denormal-operand exception masked; modify FE_ALL_EXCEPT accordingly.
By excluding the denormal-operand exception from FE_ALL_EXCEPT, it will not
be possible anymore to UNmask this exception by means of the API defined by
/usr/include/fenv.h

Note: terminology has changed since IEEE Std 854-1987; denormalized numbers
are called subnormal numbers nowadays.

This modification has basically been motivated by the fact that it is also
not possible on Linux to manipulate the denormal-operand exception by means
of the interface as defined by /usr/include/fenv.h. This has been the state
of affairs on Linux since 2001 (Andreas Jaeger).

The exceptions required by the standard (IEEE Std 754), in case they can be
supported by the implementation, are:
FE_INEXACT, FE_UNDERFLOW, FE_OVERFLOW, FE_DIVBYZERO and FE_INVALID.

Although it is allowed to define additional exceptions, there is no reason
to support the "denormal-operand exception" in this case (fenv.h), because
the subnormal numbers can be handled almost as fast the normalized numbers
by the hardware of the x86/x86_64 architecture. Said differently, a reason
to trap on the input of subnormal numbers does not exist. At least that is
what William Kahan and others at Intel asserted around 2000.
(that is William Kahan of the K-C-S draft, the precursor to the standard)

This commit modifies winsup/cygwin/include/fenv.h as follows:
 - redefines FE_ALL_EXCEPT from 0x3f to 0x3d
 - removes the definition for FE_DENORMAL
 - introduces __FE_DENORM (0x2) (enum in Linux also uses __FE_DENORM)
 - introduces FE_ALL_EXCEPT_X86 (0x3f), i.e. ALL x86/x86_64 FP exceptions
2018-08-15 18:02:22 +02:00
config Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
etc Remove spurious empty line in changelog entry. 2016-03-22 10:29:22 +01:00
include Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
libgloss Add BSP and semihosting library for nios2-generic-nommu QEMU emulation. 2018-08-08 10:53:03 +02:00
newlib Added Restriction on base value 2018-08-13 09:42:21 +02:00
texinfo * texinfo/texinfo.tex: Update to version 2009-03-28.05. 2009-04-21 12:36:46 +00:00
winsup Keep the denormal-operand exception masked; modify FE_ALL_EXCEPT accordingly. 2018-08-15 18:02:22 +02:00
.drone.yml Continuous Integration: Add Tea CI build configuration. 2016-06-28 13:42:59 +02:00
.gitattributes Add .gitattributes 2015-03-09 20:53:11 +01:00
.gitignore Add *.swp (Vim swap files) to .gitignore 2015-03-17 12:03:30 +01:00
COPYING 2005-07-14 Kelley Cook <kcook@gcc.gnu.org> 2005-07-14 01:24:56 +00:00
COPYING.LIB Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
COPYING.LIBGLOSS Add Synopsys license for newlib and libgloss 2015-11-12 14:16:32 +01:00
COPYING.NEWLIB Change license to FreeBSD License for RISC-V 2017-08-21 11:08:54 +02:00
COPYING3 * COPYING3: New file. Contains version 3 of the GNU General Public License. 2007-07-17 13:50:23 +00:00
COPYING3.LIB * COPYING3: New file. Contains version 3 of the GNU General Public License. 2007-07-17 13:50:23 +00:00
ChangeLog Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
MAINTAINERS MAINTAINERS: clarify policy with config/ (and other top level files) 2012-05-12 03:10:17 +00:00
Makefile.def Sync with upstream gcc. 2016-06-23 15:54:55 -04:00
Makefile.in Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
Makefile.tpl Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
README 19990502 sourceware import 1999-05-03 07:29:06 +00:00
README-maintainer-mode Cleanups after the update to Autoconf 2.64, Automake 1.11. 2009-08-22 17:08:06 +00:00
compile Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
config-ml.in Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
config.guess Update config.guess and config.sub 2018-07-06 10:46:43 +02:00
config.rpath Remove freebsd1 from libtool.m4 macros and config.rpath. 2011-02-13 21:00:08 +00:00
config.sub Update config.guess and config.sub 2018-07-06 10:46:43 +02:00
configure Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
configure.ac Introduce @unless/@endunless and postbootstrap Makefile targets 2018-06-30 00:12:40 -03:00
depcomp Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
djunpack.bat * djunpack.bat: Use ".." quoting in Sed command, for the sake of 2009-03-27 13:37:09 +00:00
install-sh Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
libtool.m4 Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
ltgcc.m4 * libtool.m4: Update to libtool 2.2.6. 2008-09-29 15:28:14 +00:00
ltmain.sh PR target/59788 2014-02-05 13:17:47 +00:00
ltoptions.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
ltsugar.m4 * libtool.m4: Update to libtool 2.2.6. 2008-09-29 15:28:14 +00:00
ltversion.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
lt~obsolete.m4 Sync Libtool from GCC. 2010-01-09 21:11:32 +00:00
makefile.vms 19990502 sourceware import 1999-05-03 07:29:06 +00:00
missing Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
mkdep * mkdep: New file. 1999-08-08 17:46:02 +00:00
mkinstalldirs Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
move-if-change Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00
setup.com 2009-09-01 Tristan Gingold <gingold@adacore.com> 2009-09-01 13:38:26 +00:00
src-release * src-release (do-proto-toplevel): Support subdir-path-prefixed 2013-10-15 20:45:52 +00:00
symlink-tree 2005-07-14 Kelley Cook <kcook@gcc.gnu.org> 2005-07-14 01:24:56 +00:00
ylwrap Sync toplevel with upstream GCC. 2016-03-22 10:25:20 +01:00

README

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.