On 02/26, Harry Wentland wrote:
> 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@xxxxxxx>
> ---
> 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 0c9f917a4d4b..cb842ba80ddd 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);
Hi Harry,
Can we have a #define macro for this constant? ^
Other than that, LGTM. You can add my r-b to the next version.
Thanks,
Melissa
> + } else {
> + return a;
> + }
> +
> +}
> +
> static inline s64 drm_int2fixp(int a)
> {
> return ((s64)a) << DRM_FIXED_POINT;
> --
> 2.44.0
>
