From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] ARM (Thumb) read from R15
Date: Mon, 2 Jul 2007 14:17:23 +0100 [thread overview]
Message-ID: <200707021417.25887.paul@codesourcery.com> (raw)
In-Reply-To: <200707021312.40022.uli@suse.de>
On Monday 02 July 2007, Ulrich Hecht wrote:
> On Saturday 30 June 2007 04:19, Paul Brook wrote:
> > > QEMU does not set the Thumb bit when reading from R15 in Thumb mode.
> >
> > Neither does real hardware.
>
> You are, unsurprisingly, right. The problem seems to be a different one.
> Quoting the ARM on "pop pc":
>
> "In ARM architecture 5 and above, bit[0] of the loaded value determines
> whether execution continues after this branch in ARM state or in Thumb
> state[...] In T variants of architecture version 4, bit[0] of the loaded
> value is ignored and execution continues in Thumb state[...]"
>
> My code is supposed to run on a 4T. I guess I'll have to implement an
> ARM_FEATURE_THUMB1.
As you have found out, qemu doesn't currently emulate v4t. There are a couple
of other instructions that should be disabled (blx) if you do this.
Paul
prev parent reply other threads:[~2007-07-02 13:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-28 14:31 [Qemu-devel] [PATCH] ARM (Thumb) read from R15 Ulrich Hecht
2007-06-28 15:30 ` Ulrich Hecht
2007-06-28 15:53 ` Ulrich Hecht
2007-06-30 2:19 ` Paul Brook
2007-07-02 11:12 ` Ulrich Hecht
2007-07-02 13:17 ` Paul Brook [this message]
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