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

[Peter Maydell]

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.

thanks
-- PMM