Enforcing byte-wide access to memory

Enforcing byte-wide access to memory

[Nick Williams]

Hi there,

Is there any way of enforcing that accesses to a particular region of memory
be byte-wide?

More specifically, I am involved with development of a real-time system
which needs to read values from flash RAM, which can only be accessed
byte-at-a-time. I understand that representation clauses and use of the
Volatile pragma will cause the compiler to generate the appropriate code to
view this memory as an array of bytes...

However, a structured view of the data stored there is required (i.e. I want
to be able to have Address clauses on variables to access those variables as
stored on the flash RAM).

What is the expected behaviour of an Unchecked_Conversion in these
circumstances? Is there another way of achieving the desired effect?

Thanks.

Nick Williams.

Re: Enforcing byte-wide access to memory

[Robert Dewar]

In article <3a51f063_2@nnrp1.news.uk.psi.net>,
  "Nick Williams" <nwilliams@praxis-cs.co.uk> wrote:
> Hi there,
>
> Is there any way of enforcing that accesses to a particular
> region of memory be byte-wide?

No, this is definitely something that is in the implementation
dependent area. If you can isolate such references to a single
unit, then the cleanest thing is to use a machine code
insertion to ensure that the specific instruction you want
is generated.


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