[avr-libc-dev] [bugs #10413] speedup tanh function in libm

[Eric Weddington]

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/**************************************************************************/
[bugs #10413] Latest Modifications:

Changes by: 
                Eric Weddington <address@hidden>
'Date: 
                Wed 12/22/2004 at 22:23 (America/Denver)

            What     | Removed                   | Added
---------------------------------------------------------------------------
            Priority | 5 - Normal                | 7 - High







/**************************************************************************/
[bugs #10413] Full Item Snapshot:

URL: <http://savannah.nongnu.org/bugs/?func=detailitem&item_id=10413>
Project: AVR C Runtime Library
Submitted by: 0
On: Thu 09/16/2004 at 14:41

Category:  Library
Severity:  5 - Average
Priority:  7 - High
Item Group:  None
Resolution:  None
Privacy:  Public
Percent Complete:  0%
Assigned to:  None
Originator Email:  address@hidden
Status:  Open


Summary:  speedup tanh function in libm

Original Submission:  The current code uses sinh/cosh which results in 2 calls 
to exp (each function calls it once) where the other variant (commented out in 
tanh.S) would only need it once. (it would also save 2 calls of inverse and 1 
of ldexp and saves memory by not needing cosh/sinh)

The problem is the other code has a bug. It gives to the ldexp function an 
1-byte-parameter where it should be 2 bytes. (see the 2 lines before the call 
of ldexp.)

Appended is a file which uses this other variant and has this bug fixed. (It 
speedsup  my application which uses tanh extensively about 40%.)





File Attachments
-------------------

-------------------------------------------------------
Date: Thu 09/16/2004 at 14:41  Name: tanh.S  Size: 3.71KB   By: None
my version using the corrected other variant to calculate tanh
http://savannah.nongnu.org/bugs/download.php?item_id=10413&amp;item_file_id=1676






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<http://savannah.nongnu.org/bugs/?func=detailitem&item_id=10413>

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