Re: [patch] Add support for VFP d16 layout for Cortex-M4

[Pedro Alves <palves@redhat.com>]

Hi Terry,

On 04/20/2012 02:16 PM, Terry Guo wrote:

> From: Pedro Alves [mailto:palves@redhat.com]

>> I'd like to make it clear that the guesses mechanism is a just a

>> fallback
>> mechanism, useful when its too late to change the stubs out there to
>> send the xml description to gdb themselves.  It's not the ideal way
>> forward,
>> and it can't scale beyond a few guesses.  The right thing is for
>> the stubs themselves to report the xml descriptions to GDB (with
>> qXfer:features:read),
>> not to have them depend on GDB being able to guess it.
>>
> 
> Ideally using the qXfer:features:read is the most natural way. Can you
> confirm that once it is used, the guess mechanism won't be resorted for M4?
> The code in trunk already has two guess methods for Cortex-M. I don't want
> things get messed up.


Correct.  If the target returns a xml description with qXfer:features:read,
the guess mechanism is never triggered.

> 
> Another thing in my mind is as Jonathan said before, the stub that will be
> programmed into flash is sensitive to the bytes. So I guess they may tend to
> save bytes by not returning target.xml. I am not sure what I am assuming is
> true. Please correct me if I am wrong.


-- 
Pedro Alves