Re: Migrating ARM9E codebase to ARM11

Vikash <vikashsaraogi@xxxxxxxxx> wrote:
> I'm using Codewarrior/ADS for the development and my code is highly
> optimized fix-point implementation with all the possible assembly
> optimizations done using hand-coding, only the control code is left to
> the compiler for optimizations. The code is on a bare metal and I feel
> that optimizing the code on bare metal will make more sense when
> migrating from ARM9E to ARM11 core. Any further assistance/advice from
> your side is welcome.

In order of time required...

As, John Penton said, you should make sure that the
processor is setup for maximum performance. This includes but is not
limited to:
- Determining if your application should be run in normal, or low
interrupt latency configuration.
- Enabling branch prediction.
- Enabling caches.

Technical reference manuals explaining the operations needed for an
ARM1136 and 76 can be downloaded from

http://www.arm.com/documentation/ARMProcessor_Cores/index.html

You should then consider upgrading to a newer compiler. ADS 1.2 only
explicitly supports upto ARMv5TEJ. The obvious upgrade path is RVCT 2.2
which is included in RVDS 2.2. This includes ARMv6 aware compilers and
assemblers and a newer version of CodeWarrior.

>From here on in it gets more complicated.

It may very well be that a carefully coded C implementation of your
assembler routines compiled by compiler which explictly knows about
ARMv6 and more importantly knows about scheduling for the ARM11 you
wish to target might be faster than the assembler optimised for the 9E.
This effect may become even more pronounced for future, more
complicated, processors.

Of course you may be able to get faster still by hand coding
specifically for the ARM11 you wish to target. The instruction timings
and interlock information needed to do so are contained in the TRM.

I do not believe that the ARM ARM for architecture version 6 has been
published so you would have to contact ARM for full instruction set
information. Alternatively much of the information you require is
contained in the documentation for the version of the ARM Assembler
shipped with RVCT 2.2 should you decide to upgrade toolchains.

-p
--
Paul Gotch
Software Engineer
Development Systems ARM Limited.

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