Re: [Qemu-devel] [PATCH v3 21/31] target-arm: Implement AArch64 DAIF system register

[Peter Crosthwaite]

On Fri, Feb 28, 2014 at 11:48 PM, Peter Maydell
<address@hidden> wrote:
> On 17 February 2014 00:17, Peter Crosthwaite
> <address@hidden> wrote:
>> On Sun, Feb 16, 2014 at 2:07 AM, Peter Maydell <address@hidden> wrote:
>>> Implement the DAIF system register which is a view of the
>>> DAIF bits in PSTATE.
>
>>> +static uint64_t aa64_daif_read(CPUARMState *env, const ARMCPRegInfo *ri)
>>> +{
>>> +    return env->daif;
>>> +}
>>
>> Is it better to just define the .fieldoffset and do away with the
>> default-behaving read handler? My understanding is this will avoid a
>> call out to helper context when running under TCG as well, leading to
>> a slight perf increase.
>
> I've just remembered why I didn't do this : env->daif is 32 bits,
> which means you can't use it as a fieldoffset for a 64 bit sysreg.
>

Should env->daif just be extended to 64b then?

Regards,
Peter

> thanks
> -- PMM
>