[V7 01/45] drm: Add helper for conversion from signed-magnitude

[Alex Hung]

On 2/24/25 09:07, Louis Chauvet wrote:
> 
> 
> Le 20/12/2024 à 05:33, Alex Hung a écrit :
>> From: Harry Wentland <harry.wentland at amd.com>
>>
>> CTM values are defined as signed-magnitude values. Add
>> a helper that converts from CTM signed-magnitude fixed
>> point value to the twos-complement value used by
>> drm_fixed.
>>
>> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> 
> Reviewed-by: Louis Chauvet <louis.chauvet at bootlin.com>

Hi Louis,

Thanks for reviewing.

The replies to other patches (2, 3, 5, 6, 7, 9, 10) seem to be empty (I 
checked on my inbox and on 
https://lore.kernel.org/all/44edbdfb-5e23-4c19-8c80-e7acb8b4930f@amd.com/T/#m2232bab7c543229a057123c5e762bf49c86a4148)

Did you try to send something which didn't go through?

> 
>> ---
>>   include/drm/drm_fixed.h | 18 ++++++++++++++++++
>>   1 file changed, 18 insertions(+)
>>
>> diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
>> index 1922188f00e8..0b44f2f294ce 100644
>> --- a/include/drm/drm_fixed.h
>> +++ b/include/drm/drm_fixed.h
>> @@ -78,6 +78,24 @@ static inline u32 dfixed_div(fixed20_12 A, 
>> fixed20_12 B)
>>   #define DRM_FIXED_EPSILON    1LL
>>   #define DRM_FIXED_ALMOST_ONE    (DRM_FIXED_ONE - DRM_FIXED_EPSILON)
>> +/**
>> + * @drm_sm2fixp
>> + *
>> + * Convert a 1.31.32 signed-magnitude fixed point to 32.32
>> + * 2s-complement fixed point
>> + *
>> + * @return s64 2s-complement fixed point
>> + */
>> +static inline s64 drm_sm2fixp(__u64 a)
>> +{
>> +    if ((a & (1LL << 63))) {
>> +        return -(a & 0x7fffffffffffffffll);
>> +    } else {
>> +        return a;
>> +    }
>> +
>> +}
>> +
>>   static inline s64 drm_int2fixp(int a)
>>   {
>>       return ((s64)a) << DRM_FIXED_POINT;
>