Re: [patch] Add support for ARMv7M devices.

[Jonathan Larmour <jifl at eCosCentric dot com>]

On 03/11/10 13:17, Daniel Jacobowitz wrote:
> On Wed, Nov 03, 2010 at 03:21:24AM +0000, Jonathan Larmour wrote:
>> I think there's a more general issue here about whether it's expected to
>> maintain support for existing working stub implementations such that they
>> can be used as they have been used even when GDB is upgraded. Changing the
>> interface with GDB remote stubs used to be a big no-no for GDB.
> 
> In general, I want to keep existing stubs working.  But someone who
> has access to an affected stub needs to lend a hand here; I don't and
> can't test anything.

I believe I've now worked out a solution, and it's not that complicated in
fact. See the attached patch. The key seems to be to let remote.c choose
the tdesc.

2010-11-09  Jonathan Larmour  <jifl@eCosCentric.com>

	* arm-tdep.c (arm_gdbarch_init): Allow M-profile targets' remote
	stubs to provide 'g' packets with or without FPA registers.

> With stubs out there sending both FPA-regs+fake-CPSR and
> FPA-regs+XPSR, I don't know how to make it work; in fact, I don't know
> how FPA-regs+XPSR ever worked.

It's clearly impossible to tell the difference between fake-CPSR and XPSR.
But even an XML target description can't make that case work right, so I
don't think that's too bad for us not to cope with. Unless you have some
ideas (a 'set' option seems overkill).

Jifl
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