commit. Copy the ethernet address into a local buffer, which we know
is sufficiently aligned for the width of the memory accesses that we
do. This also eliminates all suspicious and potentionally harmful
casts.
In collaboration with: ru
FreeBSD machine. To do this add the man 1 uname changes to __xuname.c
so we can override the settings it reports. Add OSVERSION override
to getosreldate. Finally which Makefile.inc1 to use uname -m instead
of sysctl -n hw.machine_arch to get the arch. type.
With these change you can put a complete FreeBSD OS image into a
chroot set:
UNAME_s=FreeBSD
UNAME_r=4.7-RELEASE
UNAME_v="FreeBSD $UNAME_r #1: Fri Jul 22 20:32:52 PDT 2005 fake@fake:/usr/obj/usr/src/sys/FAKE"
UNAME_m=i386
UNAME_p=i386
OSVERSION=470000
on an amd64 or i386 and it just work including building ports and using
pkg_add -r etc. The caveat for this example is that these patches
have to be applied to FreeBSD 4.7 and the uname(1) changes need to
be merged. This also addresses issue with libtool.
This is usefull for when a build machine has been trashed for an
old release and we want to do a build on a new machine that FreeBSD
4.7 won't run on ...
instance, the dreaded shared memory problem in PostgreSQL coming back to
haunt you after a binary update.
PR: 89817
Submitted by: edwin
MFC after: 2 days
other systems it prevents a tty from becoming a controlling tty on the
open. O_SYNC is the POSIX name for O_FSYNC.
The Markup Police may need to tweak my references to standards.
plain file bsdlabel(8) always writes label at a fixed offset from
its beginning (512 bytes), regardless of the sector size. At the same
time, bsdlabel geom class expects label to be available at the very
beginning of the second sector.
As a result, images prepared in userland for media with sector size
different from 512 bytes (i.e. 2k for cdroms) are not recognized by
the tasting mechanism.
Solve the problem by always looking for the label at 512-byte offset
if we can't find it at the beginning of the second sector and sector
size is not 512 bytes.
o The only indication of error condition is NULL value returned by
the function;
o value pointed to by error argument is undefined in the case when
operation completes successfully.
Discussed with: phk
only now) symbolic links in the kernel compile directory, rather
than relying on config(8) to do this. (The changes to config(8)
will be committed separately.) This is aimed towards making the
config(8) as lightweight as possible.
Idea by: bde (all bugs are mine)
k_tanf.c but with different details.
The polynomial is odd with degree 13 for tanf() and odd with degree
9 for sinf(), so the details are not very different for sinf() -- the
term with the x**11 and x**13 coefficients goes awaym and (mysteriously)
it helps to do the evaluation of w = z*z early although moving it later
was a key optimization for tanf(). The details are different but simpler
for cosf() because the polynomial is even and of lower degree.
On Athlons, for uniformly distributed args in [-2pi, 2pi], this gives
an optimization of about 4 cycles (10%) in most cases (13% for sinf()
on AXP, but 0% for cosf() with gcc-3.3 -O1 on AXP). The best case
(sinf() with gcc-3.4 -O1 -fcaller-saves on A64) now takes 33-39 cycles
(was 37-45 cycles). Hardware sinf takes 74-129 cycles. Despite
being fine tuned for Athlons, the optimization is even larger on
some other arches (about 15% on ia64 (pluto2) and 20% on alpha (beast)
with gcc -O2 -fomit-frame-pointer).
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.
that was used doesn't work normally here, since we want to be able to
multiply `hi' by the exponent of x _exactly_, and the exponent of x has
more than 7 significant bits for most denormal x's, so the multiplication
was not always exact despite a cloned comment claiming that it was. (The
comment is correct in the double precision case -- with the normal 33+53
bit decomposition the exponent can have 20 significant bits and the extra
bit for denormals is only the 11th.)
Fixing this had little or no effect for denormals (I think because
more precision is inherently lost for denormals than is lost by roundoff
errors in the multiplication).
The fix is to reduce the precision of the decomposition to 16+24 bits.
Due to 2 bugs in the old deomposition and numerical accidents, reducing
the precision actually increased the precision of hi+lo. The old hi+lo
had about 39 bits instead of at least 41 like it should have had.
There were off-by-1-bit errors in each of hi and lo, apparently due
to mistranslation from the double precision hi and lo. The correct
16 bit hi happens to give about 19 bits of precision, so the correct
hi+lo gives about 43 bits instead of at least 40. The end result is
that expf() is now perfectly rounded (to nearest) except in 52561 cases
instead of except in 67027 cases, and the maximum error is 0.5013 ulps
instead of 0.5023 ulps.
