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From: Daniel Jacobowitz <drow@false.org>
To: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Doug Evans <dje@google.com>, gdb-patches@sourceware.org
Subject: Re: Per-type architecture (Re: [10/15] Basic value access routines)
Date: Tue, 23 Jun 2009 17:30:00 -0000	[thread overview]
Message-ID: <20090623173016.GA29740@caradoc.them.org> (raw)
In-Reply-To: <200906231700.n5NH0Op5017747@d12av02.megacenter.de.ibm.com>

On Tue, Jun 23, 2009 at 07:00:24PM +0200, Ulrich Weigand wrote:
> We *do* need the architecture to interpret bitfield types; see e.g. the
> comment in gdbtypes.h:
> 
>       /* Position of this field, counting in bits from start of
>          containing structure.
>          For gdbarch_bits_big_endian=1 targets, it is the bit offset to the MSB.
>          For gdbarch_bits_big_endian=0 targets, it is the bit offset to the LSB.
>          For a range bound or enum value, this is the value itself. */
> 
>       int bitpos;
> 
> and the various references to gdbarch_bits_big_endian (current_gdbarch)
> in unpack_field_as_long, modify_field, etc.   There's no way to operate
> on a bitfield value without knowledge of this property.

You're right, we do - it's a very odd representation where we need the
endianness both to set and to use the position, if you ask me, but it
does tend to line up with symbol readers.

> OK, thanks.  I've checked the patch in now.

Great.  I'll let you know if I have any problems.

-- 
Daniel Jacobowitz
CodeSourcery


  reply	other threads:[~2009-06-23 17:30 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-09 15:20 [10/15] Basic value access routines Ulrich Weigand
2009-06-15 16:35 ` Doug Evans
2009-06-15 16:59   ` Ulrich Weigand
2009-06-22 20:32     ` Per-type architecture (Re: [10/15] Basic value access routines) Ulrich Weigand
2009-06-22 20:59       ` Daniel Jacobowitz
2009-06-23  0:41         ` Ulrich Weigand
2009-06-23 13:49           ` Daniel Jacobowitz
2009-06-23 14:02             ` Pedro Alves
2009-06-23 17:06             ` Ulrich Weigand
2009-06-23 17:30               ` Daniel Jacobowitz [this message]
2009-06-23 15:55           ` Doug Evans
2009-06-23 16:42             ` Mark Kettenis
2009-06-23 16:53               ` Daniel Jacobowitz
2009-06-23 16:57             ` Ulrich Weigand
2009-06-23 17:36               ` Doug Evans
2009-06-24 15:31     ` [10/15] Basic value access routines Tom Tromey
2009-06-24 15:46       ` Daniel Jacobowitz
2009-06-24 16:26         ` Doug Evans
2009-06-24 19:41           ` Tom Tromey

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