From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Ingham <jingham@cygnus.com>
To: tromey@cygnus.com
Cc: Insight List <insight@sourceware.cygnus.com>
Subject: Re: assembly display -vs- popups
Date: Mon, 17 Apr 2000 12:58:00 -0000
Message-id: <14587.28052.611834.422597@leda.cygnus.com>
References: <87bt38h5kp.fsf@cygnus.com>
X-SW-Source: 2000-q2/msg00093.html

Tom,

 > While debugging my gcj-generated stubs I always use the assembly view,
 > because there isn't any source corresponding to the code I'm
 > debugging.
 > 
 > In assembly mode I see code like this (on my x86 box):
 > 
 > -	0x403077ca	<simple_int.nat(int)+42>:		mov    %eax,0xfffffff8(%ebp)
 > 
 > If I highlight "%ebp", I'd like it to display the value of the
 > register in the balloon.  Unfortunately, it does not, because "%ebp"
 > is not valid gdb syntax for getting the register value.
 > 
 > A hack would be to do `s/%/$/' to the expression in assembly mode.

This makes me nervous.  It is not guaranteed to work everywhere.  Not
everybody uses % for registers in their standard dissassembler.  On
MIPS a $ is used.  Who knows what some other architecture might
choose...  More importantly, there is no guarantee that replacing the
% with $ is benign...

 > 
 > This is bad because ideally I'd like to be able to highlight
 > 0xfffffff8(%ebp) and have it do the right thing.  Maybe assembly needs
 > a different expression evaluator, making this a more general gdb
 > problem?

I think this is right; Insight just feeds whatever you highlight to
evaluate_expression...  The problem is that gdb doesn't seem to
evaluate assembly expressions in the format used by the disassembler,
which certainly seems wrong to me.

Jim