History log of /freebsd/lib/msun/src/s_expm1f.c (Results 26 – 33 of 33)
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# a00672cf 07-Feb-2008 Bruce Evans <bde@FreeBSD.org>

Use a better method of scaling by 2**k. Instead of adding to the
exponent bits of the reduced result, construct 2**k (hopefully in
parallel with the construction of the reduced result) and multiply

Use a better method of scaling by 2**k. Instead of adding to the
exponent bits of the reduced result, construct 2**k (hopefully in
parallel with the construction of the reduced result) and multiply by
it. This tends to be much faster if the construction of 2**k is
actually in parallel, and might be faster even with no parallelism
since adjustment of the exponent requires a read-modify-wrtite at an
unfortunate time for pipelines.

In some cases involving exp2* on amd64 (A64), this change saves about
40 cycles or 30%. I think it is inherently only about 12 cycles faster
in these cases and the rest of the speedup is from partly-accidentally
avoiding compiler pessimizations (the construction of 2**k is now
manually scheduled for good results, and -O2 doesn't always mess this
up). In most cases on amd64 (A64) and i386 (A64) the speedup is about
20 cycles. The worst case that I found is expf on ia64 where this
change is a pessimization of about 10 cycles or 5%. The manual
scheduling for plain exp[f] is harder and not as tuned.

Details specific to expm1*:
- the saving is closer to 12 cycles than to 40 for expm1* on i386 (A64).
For some reason it is much larger for negative args.
- also convert to __FBSDID().

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Revision tags: release/6.3.0_cvs, release/6.3.0, release/6.2.0_cvs, release/6.2.0, release/5.5.0_cvs, release/5.5.0, release/6.1.0_cvs, release/6.1.0, release/6.0.0_cvs, release/6.0.0, release/5.4.0_cvs, release/5.4.0, release/4.11.0_cvs, release/4.11.0, release/5.3.0_cvs, release/5.3.0, release/4.10.0_cvs, release/4.10.0, release/5.2.1_cvs, release/5.2.1, release/5.2.0_cvs, release/5.2.0, release/4.9.0_cvs, release/4.9.0, release/5.1.0_cvs, release/5.1.0, release/4.8.0_cvs, release/4.8.0, release/5.0.0_cvs, release/5.0.0, release/4.7.0_cvs, release/4.6.2_cvs, release/4.6.2, release/4.6.1, release/4.6.0_cvs
# 59b19ff1 28-May-2002 Alfred Perlstein <alfred@FreeBSD.org>

Fix formatting, this is hard to explain, so I'll show one example.

- float ynf(int n, float x) /* wrapper ynf */
+float
+ynf(int n, float x) /* wrapper ynf */

This is because the __S

Fix formatting, this is hard to explain, so I'll show one example.

- float ynf(int n, float x) /* wrapper ynf */
+float
+ynf(int n, float x) /* wrapper ynf */

This is because the __STDC__ stuff was indented.

Reviewed by: md5

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# 2dcc2286 28-May-2002 Alfred Perlstein <alfred@FreeBSD.org>

Assume __STDC__, remove non-__STDC__ code.

Reviewed by: md5


Revision tags: release/4.5.0_cvs, release/4.4.0_cvs, release/4.3.0_cvs, release/4.3.0, release/4.2.0, release/4.1.1_cvs, release/4.1.0, release/3.5.0_cvs, release/4.0.0_cvs, release/3.4.0_cvs, release/3.3.0_cvs
# 7f3dea24 28-Aug-1999 Peter Wemm <peter@FreeBSD.org>

$Id$ -> $FreeBSD$


Revision tags: release/3.2.0, release/3.1.0, release/3.0.0, release/2.2.8, release/2.2.7, release/2.2.6, release/2.2.5_cvs, release/2.2.2_cvs, release/2.2.1_cvs, release/2.2.0, release/2.1.7_cvs
# 7e546392 22-Feb-1997 Peter Wemm <peter@FreeBSD.org>

Revert $FreeBSD$ to $Id$


Revision tags: release/2.1.6_cvs, release/2.1.6.1
# 1130b656 14-Jan-1997 Jordan K. Hubbard <jkh@FreeBSD.org>

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

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Revision tags: release/2.1.5_cvs, release/2.1.0_cvs, release/2.0.5_cvs
# 6c06b4e2 30-May-1995 Rodney W. Grimes <rgrimes@FreeBSD.org>

Remove trailing whitespace.


Revision tags: release/2.0
# 3a8617a8 19-Aug-1994 Jordan K. Hubbard <jkh@FreeBSD.org>

J.T. Conklin's latest version of the Sun math library.

-- Begin comments from J.T. Conklin:
The most significant improvement is the addition of "float" versions
of the math functions that take float

J.T. Conklin's latest version of the Sun math library.

-- Begin comments from J.T. Conklin:
The most significant improvement is the addition of "float" versions
of the math functions that take float arguments, return floats, and do
all operations in floating point. This doesn't help (performance)
much on the i386, but they are still nice to have.

The float versions were orginally done by Cygnus' Ian Taylor when
fdlibm was integrated into the libm we support for embedded systems.
I gave Ian a copy of my libm as a starting point since I had already
fixed a lot of bugs & problems in Sun's original code. After he was
done, I cleaned it up a bit and integrated the changes back into my
libm.
-- End comments

Reviewed by: jkh
Submitted by: jtc

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