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Re: [Qemu-devel] When are register values committed to CPUARMState
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] When are register values committed to CPUARMState |
Date: |
Mon, 31 Mar 2014 20:17:43 +0100 |
[put qemu-devel back on CC]
On 31 March 2014 20:13, Gaurav Sharma <address@hidden> wrote:
> On Mon, Mar 31, 2014 at 11:35 PM, Peter Maydell <address@hidden>
> wrote:
>> On 31 March 2014 18:59, Gaurav Sharma <address@hidden> wrote:
>> > I want to know, when are the register values committed to CPUARMState
>> > structure ?
>>
>> When they need to be. Mostly we keep register values in TCG
>> globals,
>
> >> By TCG globals here do we mean, cpu_R[] array, because if i see the
> code for a simple add, i can see source and destination values for the TCG
> ops being this array? In the init function isn't this array mapped on to
> CPUARMState ?
Yes, but...
>> which means they're held in host registers except
>> when calling helpers which might read or write globals
...as I say TCG is free to keep globals in host registers
a lot of the time and only writes values back to the
CPUARMState when it needs to.
thanks
-- PMM