[U-Boot] [PATCH 2/8] armv7: cache maintenance operations for armv7

Aneesh V
2011-01-13T14:30:20Z

On Thursday 13 January 2011 06:44 PM, Albert ARIBAUD wrote:
> Le 13/01/2011 13:05, Aneesh V a ?crit :
>
>>>> What I need is something like below:
>>>>
>>>> #define get_bit_field(nr, start, mask)\
>>>> (((nr) & (mask)) >> (start))
>>>>
>>>> #define set_bit_field(nr, start, mask, val)\
>>>> (nr) = ((nr) & ~(mask)) | (((val) << (start)) & (mask))
>>>>
>>>> Can these go in a generic header? If so, can I add them to
>>>> "include/linux/bitops.h"
>>>
>>> After some more thought, I am wondering if a *generic* field setting and
>>> getting macro is really useful. So far everyone is fine with at most
>>> defining field-specific macros.
>>
>> Is it going to be easy if you have many fields to deal with?
>
> I don't see how the generic macros ease anything. Instead of defining say
>
> #define get_field_F(x) ((x >> F_start) & F_mask)
> #define set_field_F(x,v) { x = (x ~ F_mask ) | (v << F_start) }
>
> You'd have
>
> #define get_field_F(x) get_bit_field(x, F_start, F_mask)
> #define set_field_F(x,v) set_bit_field(x, F_start, F_mask, v);
>
> Which does not seem to bring any simplicity to me.

I wouldn't define get_field_F.
Instead I would just use set_bit_field(x, F_start, F_mask, v) directly
in the code and I have F_start and F_mask defined in the header files
(automatically generated)

Even if it was manual isn't it easier to define just F_start and F_mask
per field than defining a get_field_F per field?

Perhaps my requirement is different. If this scheme is not used by
many, I shall put these macros in OMAP specific headers.

best regards,
Aneesh