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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Vincent Sanders <vince@simtec.co.uk>
Subject: Re: [Qemu-devel] Add ARM920T to ARM emulation
Date: Fri, 29 May 2009 23:05:28 +0100	[thread overview]
Message-ID: <200905292305.28740.paul@codesourcery.com> (raw)
In-Reply-To: <1243603405-12989-1-git-send-email-vince@simtec.co.uk>

> There was some discussion of the differences between v4 and v5 with
> respect to LDR behaviour manipulating the program counter when the
> bottom bit of an adress is set. The ARM-ARM clearly defines such
> behaviour as "unpredicatble" (section A2.4.3 page 48) where it says
> "In all variants of ARMv4 and ARMv5, bits[1:0] of a value written to
> R15 in ARM state must be 0b00. If they are not, the results are
> UNPREDICTABLE." .

This statement is only applies to instructions that do not have explicit 
semantics for r15. Use of r15 as a destination in load/pop instructions is 
well defined.

Paul

  parent reply	other threads:[~2009-05-29 22:05 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-29 13:23 [Qemu-devel] Add ARM920T to ARM emulation Vincent Sanders
2009-05-29 13:23 ` [Qemu-devel] [PATCH 1/1] Update ARM emulation to be version 4t by default Vincent Sanders
2009-05-29 21:59   ` Paul Brook
2009-05-30 10:08     ` Vincent Sanders
2009-05-29 22:05 ` Paul Brook [this message]
2009-06-01 11:35   ` [Qemu-devel] Add ARM920T to ARM emulation Jamie Lokier
2009-06-01 12:13     ` Paul Brook
2009-06-01 13:29       ` Avi Kivity
2009-06-01 13:48         ` Tristan Gingold
2009-06-01 13:58           ` Avi Kivity
2009-06-01 16:34         ` Paul Brook
2009-06-01 23:11       ` Jamie Lokier

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