diff options
| author | Harry Wentland <harry.wentland@amd.com> | 2025-11-14 17:01:26 -0700 |
|---|---|---|
| committer | Simon Ser <contact@emersion.fr> | 2025-11-26 22:16:13 +0100 |
| commit | 4fc183828b050c1d7d94347c876c04a5b680b4fc (patch) | |
| tree | 5c9c4e34c045f467a8c6d2cb6177bce2b767b49b | |
| parent | c884ee70b15a8d63184d7c1e02eba99676a6fcf7 (diff) | |
drm: Add helper for conversion from signed-magnitude
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.
Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Simon Ser <contact@emersion.fr>
Link: https://patch.msgid.link/20251115000237.3561250-2-alex.hung@amd.com
| -rw-r--r-- | include/drm/drm_fixed.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h index 1922188f00e8..33de514a5221 100644 --- a/include/drm/drm_fixed.h +++ b/include/drm/drm_fixed.h @@ -78,6 +78,23 @@ 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; |