From: Nate Eldredge <neldredge AT hmc DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: GDB and FSDB - getting x86 specific info (page tables, ldt, gdt)
Date: 01 Jun 2001 12:20:47 -0700
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"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> writes:

> > From: Nate Eldredge <neldredge AT hmc DOT edu>
> > Newsgroups: comp.os.msdos.djgpp
> > Date: 31 May 2001 23:58:24 -0700
> > > 
> > > Please define ``dump memory''.  GDB generally displays memory
> > > addresses as variables; if you mean ``dump memory'' the DEBUG.COM
> > > style, then it cannot do that, even for memory that is part of the
> > > normal DS selector addressable range.  
> > 
> > What about the `x' command?  That certainly can dump memory in a
> > format rather like debug's.
> 
> Not without some tricky use of GDB advanced features, such as
> ``artifical arrays''.

Huh?  A command like

x/32x 0xaddress

doesn't seem especially tricky or advanced to me.

Well, maybe it will help the poster anyway.

...

> > I suspect you can sort of cheat to dump memory in other selectors.  I
> > haven't tried this, but here's an idea:
> > 
> > set $p = start_address
> > while ($p < end_address)
> >         print/x _farpeekb(selector, $p++)
> > end
> 
> I don't think this will work: _far* functions expand into inline
> assembly, so GDB will think they don't exist in the executable.

But out-of-line versions exist in the library, and the code snippet I
posted should force them to be compiled in.

> Anyway, whether or not this is appropriate for accessing memory
> through other selectors depends on the intended usage.  Without the
> details from the OP, I cannot tell.

True.  It was just a thought.

-- 

Nate Eldredge
neldredge AT hmc DOT edu