Re: [Qemu-arm] [Qemu-devel] [PATCH 1/2] softfloat: Enable run-time-configurable meaning of signaling NaN bit

[Peter Maydell]

On 4 April 2016 at 20:37, Eduardo Habkost <address@hidden> wrote:
> On Mon, Apr 04, 2016 at 02:31:47PM +0100, Peter Maydell wrote:
>> On 4 April 2016 at 14:21, Aleksandar Markovic
>> <address@hidden> wrote:
>> > B. arm - explicitely sets other fields of float_status,
>> >       explicit invocation of set_snan_bit_is_one(0) added
>>
>> We zero the float_status structs on reset, because they are earlier
>> in the CPUARMState structure than the 'features' field (and so the
>> memset() in arm_cpu_reset() will clear them). So you don't
>> need to explicitly zero a field like this. I expect the other
>> architectures are the same.
>
> Even if it is not zeroed on reset, it is zeroed on object_new().
> Isn't that enough?

It must be zeroed on reset, otherwise we won't get the right
behaviour if you reset the CPU after running it for a bit.
object_new() zeroing is not sufficient.

thanks
-- PMM