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Re: [Qemu-ppc] PPC: Which instruction to fetch at Power-On?
From: |
Fabien Chouteau |
Subject: |
Re: [Qemu-ppc] PPC: Which instruction to fetch at Power-On? |
Date: |
Thu, 28 Mar 2013 16:10:01 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 |
On 03/28/2013 12:46 PM, Alexander Graf wrote:
>
> On 28.03.2013, at 12:42, Fabien Chouteau wrote:
>
>>
>> While working on a patch to remove env->hreset_excp_prefix, I'm looking
>> at which instruction should be the fetched first at power-on. I'm lost
>> in all the PPC version and configuration, can anyone (Alex :) can help
>> me with this mess?
>
> Phew - I'd say just keep the targets you don't know exactly as they are :).
> That way you at least don't break anything that wasn't broken before.
>
> For the targets where you do know better (like 7x0), change its behavior to
> be correct according to the respective spec.
>
Here's what I found in the UM of almost all the cores supported by QEMU:
Every CPU should start at the hreset address (i.e. excp_prefix + 0x100).
However, some cores don't have a hreset exception (4xx and Book E (e200,
e500)), those cores start at 0xFFFF_FFFC.
--
Fabien Chouteau