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Re: [avr-libc-dev] [bug #12739] Gcc assumes that target libc provides ff


From: E. Weddington
Subject: Re: [avr-libc-dev] [bug #12739] Gcc assumes that target libc provides ffs function
Date: Wed, 20 Apr 2005 16:53:23 -0600
User-agent: Mozilla Thunderbird 1.0.2 (Windows/20050317)

Dmitry K. wrote:

On Wednesday 20 April 2005 06:31, Joerg Wunsch wrote:
As Eric Weddington wrote:
For reference, the ffs function can be found in newlib.
<http://sources.redhat.com/newlib/libc.html#SEC187>
Which probably took it straight from the BSD lib. ;-)

As the function is so simple, and the BSD copyright matches our
copyright (clause 3 may officially be omitted), we can easily import
it.

I have look 'ffs' from newlib (1.12.0).  It take up to 800 (!) clocks.
Reason: shift is included to loop.

My realisation for AVR:
   ffs:   12 words, 39 clocks max
   ffsl:  18 words, 45 clocks max
   ffsll: 30 words, 57 clocks max

I shall send it after all tests writing.

Fantastic!

Thanks for doing this.
Eric




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