Re: PATCH: Support x86 pseudo registers

Pedro Alves
2010-03-12T15:26:47Z

On Friday 12 March 2010 08:30:50, Eli Zaretskii wrote:
> > From: Pedro Alves <pedro@codesourcery.com>
> > Date: Fri, 12 Mar 2010 04:23:07 +0000
> > Cc: "H.J. Lu" <hjl.tools@gmail.com>,
> > msnyder@vmware.com
> >
> > I just realized that this change means that $sp is now just
> > a 16-bit word of $esp, instead of a pseudo-register resolving to
> > either $esp/$rsp (32-bit/64-bit). I can't say it is actually wrong to
> > have it that way
>
> I think it's very wrong, because it means we no longer have a generic
> stack pointer register, at least not on x86. Is that true?

A certainly agree very much that it's not convenient to have
$sp not be the largest stack pointer. I said the above based on:

@cindex standard registers
@value{GDBN} has four ``standard'' register names that are available (in
expressions) on most machines---whenever they do not conflict with an
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
architecture's canonical mnemonics for registers. The register names
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@code{$pc} and @code{$sp} are used for the program counter register and
the stack pointer. @code{$fp} is used for a register that contains a
pointer to the current stack frame, and @code{$ps} is used for a
register that contains the processor status. For example,
you could print the program counter in hex with

So, should that sentence of the manual be relaxed? I guess
this would be a good place to at least mention the x86 $sp is
always $esp or $rsp.

--
Pedro Alves