Re: Examining individual bytes of an integer

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 18-10-19 00:18 , Randy Brukardt wrote:
> "AdaMagica" <christ-usch.grein@t-online.de> wrote in message
> news:39be8a25-cc06-4db4-9481-7f484077522d@googlegroups.com...
> ...
>> There remains the other statement:
>> "By reasonable induction  :-)  the second, third, etc. array elements
>> follow in increasing address order. But not _guaranteed_, I agree."
>>
>> I still claim that this has too be true (of course with a grain of salt for
>> packead arrays).
>
> I agree, it would make indexing calculations really expensive if it isn't
> true. And I don't see a compiler author doing that on purpose.

Oh, I'm not so sure... Storing by *reverse* index order should not be 
much more expensive, if at all. I seem to remember hearing about a 
Pascal compiler in which record components were stored in reverse 
lexical declaration order, just because of the way the compiler turned 
out, or so I understood.

And the people working on probabilistic WCET analysis want to randomize 
lots of things, such as cache address mappings, and are creating HW 
processors with such features. Perhaps they would like to randomize also 
array component order...

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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