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Re: [avr-gcc-list] How to (efficeiently !!!) test a bit within a multi-b

From: Vincent Trouilliez
Subject: Re: [avr-gcc-list] How to (efficeiently !!!) test a bit within a multi-byte integer ?
Date: Sat, 05 Nov 2005 01:28:03 +0100

> >I compiled 3.4.3 ... does 3.4.4 or 4.0 do a better job at it ?
> >  
> >
> With gcc-3.4.4 and -Os, the compiler loads 4 registers with the 32 bits 
> value (address) and then use 'sbrs <register>,2' to perform the test. 
> Hence it is very fast. It would be faster if it needs only one register 
> to test however. I did not test with gcc-4.x
> Bernard

Hmmm, it's interesting to see that 3.4.4 is that much better than
3.4.3 ! It means that avr-gcc is being actively improved, that's rather
encouraging, at this pace, in 2 or 3 years, it will rival or better the
most expensive commercial compilers :o) Long may live Unix/Linux and
open source...


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