On 08/12/14 13:59, Damien Lespiau wrote:
> On Mon, Dec 08, 2014 at 02:33:57PM +0200, Jani Nikula wrote:
>>> #define _MASKED_BIT_ENABLE(a) (((a) << 16) | (a))
>>> #define _MASKED_BIT_DISABLE(a) ((a) << 16)
>>> +#define _MASKED_FIELD(value, mask) (((mask) << 16) | (value))
>>
>> Obligatory bikeshed, wouldn't you say _MASKED_BIT_{ENABLE,DISABLE} are
>> special cases of _MASKED_FIELD...? ;)
>
> That's because we're not just enabling or disabling bits here but
> setting a multi-bits value.
>
> _MASKED_FIELD(2 << 4, 0x3 << 4);
>
So you could
#define __MASKED_BIT_DISABLE(a) (__MASKED_FIELD(0, (a)))
#define __MASKED_BIT_ENABLE(a) (__MASKED_FIELD((a), (a)))
which I think is what Jani was referring to ...
Bikeshed++: do we care about the double evaluation of (a) in these macros?
.Dave.
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