Re: GCC and Memory Organization

[Glynn Clements <glynn.clements@virgin.net>]

William N. Zanatta wrote:

>    I have a question on memory organization...
>    In my Computer Architeture classes, I've learned something like that 
> there are two ways to organize data in memory.
>    The first one puts it in a linear mode like:
> 
>       +---------------+
> 12k  | z | z |   |   |
>       |---------------|
> 8k   | y | y | z | z |
>       |---------------|
> 4k   | x | x | x | y |
>       +---------------+
> 
>    And the second way is a non-linear, a block mode like:
> 
>       +---------------+
> 12k  | z | z | z | z |
>       |---------------|
> 8k   | y | y | y |   |
>       |---------------|
> 4k   | x | x |   |   |
>       +---------------+
> 
>    The second way should be faster than the first one for memory 
> management, right?! That a kindda obviuos as it wouldn't be necessary to 
> scan all the block to find the next entry. Also it can be expensive 
> since the 4k block is allocated for only 2k of real data.
> 
>    My question is, how does GCC works with this? Does it have any switch 
> for optimizing (or not) the code?? What's the default action???

This isn't a compiler issue. The different layouts would require
different source code. The former corresponds to a one-dimensional
array, while the latter corresponds to a two-dimensional array.

-- 
Glynn Clements <glynn.clements@virgin.net>