From: Ian Lance Taylor <ian@zembu.com>
To: alan@linuxcare.com.au
Cc: ac131313@cygnus.com, binutils@sourceware.cygnus.com,
gdb-patches@sourceware.cygnus.com
Subject: Re: [rfc] For mips, sign-extended ecoff offsets
Date: Mon, 19 Jun 2000 20:39:00 -0000 [thread overview]
Message-ID: <20000620033908.18201.qmail@daffy.airs.com> (raw)
In-Reply-To: <Pine.LNX.4.21.0006201128050.12273-100000@front.linuxcare.com.au>
Date: Tue, 20 Jun 2000 11:50:26 +1000 (EST)
From: Alan Modra <alan@linuxcare.com.au>
> > I'm worried about what happens if things like PDR.adr get changed from
> > 0xa0000000 to 0xffffffffa0000000.
>
> Thats why I'm asking :-) Remember though, on the MIPS platform, if
> ``PDR.adr'' is an address then, the canonical form of the value
> ``0xa0000000'' obtained from an elf32 binary is 0xffffffffa00000000.
> GDB and BFD have, for too many years, been bribed and cajoled into
> perpetuated the lie that MIPS doesn't sign extend addresses. GDB's now
> decided to come clean on this matter (and purge an amazing amount of
> bogus code :-).
> I guess the question for BFD people is, is this the correct approach to
> fixing this bug?
I'd like to hear Ian's comments on this before you check it in.
This is all due to a long-ago decision to ship support for a 64-bit
MIPS chip using a 32-bit MIPS target. I think that sign extending
pdr.ADR is probably right, since that is how 32 bit addresses are
treated by the relocation routines. But the real fix is to use a
64-bit MIPS target.
Ian
next prev parent reply other threads:[~2000-06-19 20:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-06-19 5:14 Andrew Cagney
2000-06-19 8:48 ` Alan Modra
2000-06-19 18:18 ` Andrew Cagney
2000-06-19 18:47 ` Ulf Carlsson
2000-06-19 18:57 ` Alan Modra
2000-06-19 19:16 ` Andrew Cagney
2000-06-19 20:08 ` Geoff Keating
2000-06-19 20:41 ` Ian Lance Taylor
2000-06-25 14:13 ` Ralf Baechle
[not found] ` <14670.59816.517716.492387@calypso.engr.sgi.com>
2000-06-19 21:30 ` Geoff Keating
2000-06-19 18:50 ` Alan Modra
2000-06-19 19:23 ` Andrew Cagney
2000-06-19 20:39 ` Ian Lance Taylor [this message]
2000-06-23 0:28 ` Andrew Cagney
2000-06-23 9:48 ` Ian Lance Taylor
2000-07-03 23:47 ` Andrew Cagney
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