Re: Avr-libc-user-manual: "Problems with reordering code"

Bob Paddock <[email protected]> Thu, 9 Feb 2017 13:49:06 -0500
Newsgroups gmane.comp.hardware.avr.gcc
Message-ID <CAOuGh8_suAqZY-w2Q7NHcevxCRccq_zh_hNy1fPB=cxoVo-+8Q@mail.gmail.com>
On Thu, Feb 9, 2017 at 1:13 PM, David Brown <[email protected]> wrote:

> Note also that it is only control
> of the memory access that is needed for code correctness - moving
> instruction execution affects timing, but not the results.

As I'm sure you are aware even if the code if mathematically correct,
giving the correct answers, failing to meet timing goals can be
catastrophic in Real Time Systems.

So the only solution is to use different parts, such as ARM, with its
Instruction Synchronization Barrier (ISB) [that can waste thousands of
cycles]?