[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [avr-chat] Missed Optimisation ?
From: |
Erik Christiansen |
Subject: |
Re: [avr-chat] Missed Optimisation ? |
Date: |
Wed, 2 Mar 2011 01:38:29 +1100 |
User-agent: |
Mutt/1.5.17+20080114 (2008-01-14) |
On Tue, Mar 01, 2011 at 03:11:14PM +0100, address@hidden wrote:
> On Wed, 2 Mar 2011 01:04:44 +1100
> Erik Christiansen <address@hidden> wrote:
>
> > IANA "volatile" expert, but understand that "[hardware|other thread]
> > may change the value while this code is executing" is a legitimate
> > view of the compiler's perspective. In that case, the whole value
> > must be read and rewritten, to avoid composite values, partly
> > software created, and partly hardware-(or alternate thread)-written.
> > reading and writing only some bytes is not a reliable option with a
> > predictable outcome.
>
> OK, neither am I a. But if the whole value must be read and rewritten
> the compiler better insert interrupt disable/enable for volatiles
> larger than 8 bits.
If that isn't needed, then it's not a volatile, I think.
(Because it's in RAM, so only another thread/ISR can intrude.
Hardware writes don't apply in this case.)
Erik
- [avr-chat] Missed Optimisation ?, bob, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Graham Davies, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Alex Eremeenkov, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Graham Davies, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Erik Christiansen, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, bob, 2011/03/01
- RE: [avr-chat] Missed Optimisation ?, Colin O'Flynn, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Graham Davies, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Erik Christiansen, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, bob, 2011/03/01
- Message not available
- [avr-chat] Re: Fasching, bob, 2011/03/02
- Re: [avr-chat] Re: Fasching, Erik Christiansen, 2011/03/02
- Re: [avr-chat] Missed Optimisation ?, Graham Davies, 2011/03/01
- RE: [avr-chat] Missed Optimisation ?, Colin O'Flynn, 2011/03/01
- Re: [avr-chat] Missed Optimisation ?, Graham Davies, 2011/03/01