On 2018-07-03 08:14, Kalle Valo wrote:
> Pkshih <pkshih@xxxxxxxxxxx> writes:
>
>> On Fri, 2018-06-29 at 10:30 +0300, Kalle Valo wrote:
>>> Pkshih <pkshih@xxxxxxxxxxx> writes:
>>>
>>> > On Tue, 2018-05-29 at 08:18 +0300, Kalle Valo wrote:
>>> >> <pkshih@xxxxxxxxxxx> writes:
>>> >>
>>> >
>>> > Because C2H data is little endian order, the struct will look like
>>> > struct foo {
>>> > #ifdef __LITTLE_ENDIAN
>>> > u8 bar:4;
>>> > u8 koo:4;
>>> > #else
>>> > u8 koo:4;
>>> > u8 bar:4;
>>> > #endif
>>> > }
>>>
>>> With u8 you don't need endian check, right? I would assume that with
>>> both little and big endian bar and koo would be in the same place.
>>
>> I think u8 with bitfield would be different between little and big endian
>> machines.
>
> To me that does not make any sense, I have never heard about bit
> endianness any of the devices I have worked on.
Unfortunately, the order in which these fields are laid out is different
between big and little endian, even when only dealing with u8.
That alone is a strong reason to avoid bitfields entirely for anything
shared between the host and something else.
- Felix
