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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Vincent Sanders <vince@simtec.co.uk>, Avi Kivity <avi@redhat.com>
Subject: Re: [Qemu-devel] Add ARM920T to ARM emulation
Date: Mon, 1 Jun 2009 17:34:56 +0100	[thread overview]
Message-ID: <200906011734.57129.paul@codesourcery.com> (raw)
In-Reply-To: <4A23D7B0.9050706@redhat.com>

On Monday 01 June 2009, Avi Kivity wrote:
> Paul Brook wrote:
> > B is a direct branch that never changes mode. BX is an indirect branch
> > that mode switches based on the low address bit.
> > BL and BLX(register) are exactly the same as B/BX except they also set
> > LR. BLX(immediate) is a direct mode switching call.
> > loads into the PC either ignore(v4t) or mode switch (v5) on the low
> > address bit.
> > ALU writes to the PC always ignore the low bit in Thumb mode. In ARM mode
> > the low bit is either ignored(v6) or used to mode switch (v7).
> >
> > BX was introduced in v4t, BLX was introduced in v5.
>
> Does no sane instruction set exist?

Thumb mode definitely has several "entertaining" aspects, but ARM mode is 
generally fairly sane.

Paul

  parent reply	other threads:[~2009-06-01 16:35 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 ` [Qemu-devel] Add ARM920T to ARM emulation Paul Brook
2009-06-01 11:35   ` 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 [this message]
2009-06-01 23:11       ` Jamie Lokier

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