[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [avr-gcc-list] How to (efficeiently !!!) test a bit within amulti-by

From: Niklas Lövgren
Subject: RE: [avr-gcc-list] How to (efficeiently !!!) test a bit within amulti-byte integer ?
Date: Sat, 5 Nov 2005 19:42:14 +0100

That's interesting it makes that much differnce between the minors. So how
much "better" is gcc 4.x.x? 
And also why isn't the newer gcc versions included in a winavr release?


-----Original Message-----
From: address@hidden
[mailto:address@hidden On Behalf Of
Vincent Trouilliez
Sent: den 5 november 2005 01:28
To: avr-gcc
Subject: Re: [avr-gcc-list] How to (efficeiently !!!) test a bit within
amulti-byte integer ?

> >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...


AVR-GCC-list mailing list

reply via email to

[Prev in Thread] Current Thread [Next in Thread]