Lpc2000

--- In lpc2000@yahoogroups.com, "philips_apps" <philips_apps@...> wrote:
>
> Hi,
>
> have a look at the FAQ here:
>
> http://www.standardics.philips.com/support/faq/microcontrollers/
>
> I also added a link in the link section named
> "Philips FAQ for LPC2000 devices"
>
> Regards, Robert
>

Hi Robert,
Great starting point. However, I find the information (below) inaccurate
(re: number of registers in Thumb state):
'Hi registers', r8-r15, are still present, it is that only instructions
ADD, MOV and CMP can make use of them.

See Steve Furber, pg 190;  and David Seal's ARM ARM, section 6.4.1

This is quite common misperception about Thumb state.

I hope this clarification is taken in a constructive way.

Best regards

Roger


Q: Having the Thumb core allows more compact code and better
performance. Are there any trade offs?    A:  Thumb is a 16-bit
compressed instruction set that is decoded by theThumb core into full
32-bit instructions that are then fed into an ARMcore for execution.
Thumb increases code density drastically. The tradeoffs are that the
Thumb instruction set loses the conditionalinstruction capability and
can only address the first eight registers of the processor.


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