Re: [ECOS] MIPS32 gdb vectors question

[Nick Garnett <nickg at ecoscentric dot com>]

"Tim Michals" <t dot michals at attbi dot com> writes:

> See below for replies....
> ----- Original Message -----
> From: "Jonathan Larmour" <jifl at eCosCentric dot com>
> To: "Tim Michals" <t dot michals at attbi dot com>
> Cc: <ecos-discuss at sources dot redhat dot com>
> Sent: Thursday, February 27, 2003 12:24 AM
> Subject: Re: [ECOS] MIPS32 gdb vectors question
> 
> 
> > Tim Michals wrote:
> >  > Ok, I have narrowed down the problem
> >  > 1) Using a ROMRAM configuration for MIPS32 and had to change
> >  > to
> >  > hal_vsr_table = 0x80000300;
> >  > hal_virtual_vector_table = 0x80000400;
> >  > from:
> >  > hal_vsr_table = 0x80000200;
> >  > hal_virtual_vector_table = 0x80000300;
> >  > A slight collision with the debug vector.
> >  >
> >  > 2) had a memory configuration issue pushing the _hal_registers past
> memory.
> >  > (Fixed(
> >
> > Ah, both things specific to your platform then.
> >
> This is for a ROMRAM configuration, If the Atlas or any other MIPS32
> platform is using mips_mips32.ld in hal/packages/mips32/src, would have this
> problem.  This is due to the copy of ROM into RAM and setting the exception
> vectors to RAM.  At this time MIPS32 does not support ROMRAM configuration.

Yup, the MIPS32 stuff has only been tested in restricted circumstances
-- mostly just RedBoot support for GNUPro. Also, these numbers
were probably inherited from some other platform that didn't have the
same set of vectors.

I was going to say that I would make the change and check it
in. However, on second thoughts, this is not a good idea, since it
renders all older redboots and ecoses incompatible with new ones. 

> >
> > Yes. GDB is expecting 32-bit registers and the stub for mips32 gives it
> > 64-bit. Look at the grotty ifdefs in
> hal/mips/arch/current/include/mips-stub.h
> >
> > Nick was doing a patch for this I thought, so I've prodded him a little
> :-).
> If not, I can fix this and test on a MIPS32 platform.

I'll be checking these changes in this evening.

-- 
Nick Garnett                    eCos Kernel Architect
http://www.ecoscentric.com/     The eCos and RedBoot experts


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