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Date: Sat, 05 Nov 2005 02:59:00 -0000
From: Wu Zhou <woodzltc@cn.ibm.com>
To: Michael Snyder <msnyder@redhat.com>
cc: gdb@sources.redhat.com, mysea000@163.com
Subject: Re: who can explain the pseudo-registers and its mechanism to
 me?thanks
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Message-ID: <Pine.LNX.4.63.0511051058120.25039@linux.site>
References: <436BB1E7.10907@redhat.com>
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On Fri, 4 Nov 2005, Michael Snyder wrote:

> "ayang" <mysea000 at 163 dot com> wrote:
> > hello,
> >      I am puzzled by the the pseudo-registers and its mechanism when I >
> read the gdb source.It is not described in gdbint.who can explain the >
> pseudo-registers and its mechanism to me?thanks.
> 
> Pseudo-registers are fake registers that do not exist
> (at least as represented) on the target.  The basic distinction
> is that gdb fetches the values of "real" registers from the
> target, but computes or composes the values of "pseudo" registers
> locally.  An example might be a double-wide pseudo-register
> that is composed from the values of two ordinary registers.
> GDB fetches the values of the two ordinary registers, but
> then combines them to produce the value of the pseudo-register.
> 
> If a user changes the value of the pseudo-register, it may
> be necessary for gdb to change the target values from which
> the pseudo-register was composed.
> 

Good explanation.  At least for me. :-) Maybe this can get into <<GDB 
internal>>?

Just my two cents anyway.

Regards
- Wu Zhou