ARM: where are special registers?

ARM: where are special registers?

[Dmitry Smirnov]

Hi, 

As you know, ARM processor have some special registers like CPSR, SPSR_svc, r8_usr, etc.
While running GDB I cannot see these registers (CPSR only).
My GDB is connected to remote ARM simulator, so maybe the simulator is the problem area?

Just as an example, session of Eclipse debugger:

248-data-list-register-names
248^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7","r8","r9","r10","r11","r12","sp","lr","pc","f0","f1","f2","f3","f4","f5","f6","f7","fps","cpsr","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","",""]

My GDB is 
GNU gdb (GDB) 6.8.50.20080630
This GDB was configured as "--host=i686-pc-cygwin --target=arm-elf".

Dmitry

Re: ARM: where are special registers?

[Daniel Jacobowitz]

On Tue, Jul 08, 2008 at 01:07:51PM +0400, Dmitry Smirnov wrote:
> Hi, 
> 
> As you know, ARM processor have some special registers like CPSR, SPSR_svc, r8_usr, etc.
> While running GDB I cannot see these registers (CPSR only).
> My GDB is connected to remote ARM simulator, so maybe the simulator is the problem area?

Please see the manual chapter on Target Descriptions - that describes
how to report additional registers.

-- 
Daniel Jacobowitz
CodeSourcery

Re: ARM: where are special registers?

[Dmitry Smirnov]

I've found in ch.11.1 at http://sourceware.org/gdb/current/onlinedocs/gdbint_11.html#SEC89 :
<quote>
A description may come from a user specified file (XML), the remote `qXfer:features:read' packet (also XML), or from any custom to_read_description routine in the target vector. For instance, the remote target supports guessing whether a MIPS target is 32-bit or 64-bit based on the size of the `g' packet.
<quote/>

Is there any example of this XML?
What remote stub shall respond to "qXfer:features:read"? Just this XML content?
Am I right that before GDB asks for "qXfer:features:read", I shall implement "qSupported" handling in a stub with this "qXfer:features:read" as a response?

-----Original Message-----
From: Daniel Jacobowitz <drow@false.org>
To: Dmitry Smirnov <divis1969@mail.ru>
Date: Tue, 8 Jul 2008 08:08:01 -0400
Subject: Re: ARM: where are special registers?

> 
> On Tue, Jul 08, 2008 at 01:07:51PM +0400, Dmitry Smirnov wrote:
> > Hi, 
> > 
> > As you know, ARM processor have some special registers like CPSR, SPSR_svc, r8_usr, etc.
> > While running GDB I cannot see these registers (CPSR only).
> > My GDB is connected to remote ARM simulator, so maybe the simulator is the problem area?
> 
> Please see the manual chapter on Target Descriptions - that describes
> how to report additional registers.
> 
> -- 
> Daniel Jacobowitz
> CodeSourcery
> 

Re: ARM: where are special registers?

[Daniel Jacobowitz]

On Tue, Jul 08, 2008 at 05:38:55PM +0400, Dmitry Smirnov wrote:
> I've found in ch.11.1 at http://sourceware.org/gdb/current/onlinedocs/gdbint_11.html#SEC89 :
> <quote>
> A description may come from a user specified file (XML), the remote `qXfer:features:read' packet (also XML), or from any custom to_read_description routine in the target vector. For instance, the remote target supports guessing whether a MIPS target is 32-bit or 64-bit based on the size of the `g' packet.
> <quote/>
> 
> Is there any example of this XML?

There are several in the manual, and in the GDB source directory
(gdb/features/).

> What remote stub shall respond to "qXfer:features:read"? Just this XML content?
> Am I right that before GDB asks for "qXfer:features:read", I shall implement "qSupported" handling in a stub with this "qXfer:features:read" as a response?

Take a look at the rmeote protocol section of the manual, which is
referenced from that chapter; it explains the details.

-- 
Daniel Jacobowitz
CodeSourcery