diff options
Diffstat (limited to 'include/drm/drm_fixed.h')
| -rw-r--r-- | include/drm/drm_fixed.h | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h index d639049a6..553210c02 100644 --- a/include/drm/drm_fixed.h +++ b/include/drm/drm_fixed.h @@ -73,18 +73,28 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) +#define DRM_FIXED_EPSILON 1LL +#define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON) static inline s64 drm_int2fixp(int a) { return ((s64)a) << DRM_FIXED_POINT; } -static inline int drm_fixp2int(int64_t a) +static inline int drm_fixp2int(s64 a) { return ((s64)a) >> DRM_FIXED_POINT; } -static inline unsigned drm_fixp_msbset(int64_t a) +static inline int drm_fixp2int_ceil(s64 a) +{ + if (a > 0) + return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE); + else + return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE); +} + +static inline unsigned drm_fixp_msbset(s64 a) { unsigned shift, sign = (a >> 63) & 1; @@ -136,6 +146,45 @@ static inline s64 drm_fixp_div(s64 a, s64 b) return result; } +static inline s64 drm_fixp_from_fraction(s64 a, s64 b) +{ + s64 res; + bool a_neg = a < 0; + bool b_neg = b < 0; + u64 a_abs = a_neg ? -a : a; + u64 b_abs = b_neg ? -b : b; + u64 rem; + + /* determine integer part */ + u64 res_abs = div64_u64_rem(a_abs, b_abs, &rem); + + /* determine fractional part */ + { + u32 i = DRM_FIXED_POINT; + + do { + rem <<= 1; + res_abs <<= 1; + if (rem >= b_abs) { + res_abs |= 1; + rem -= b_abs; + } + } while (--i != 0); + } + + /* round up LSB */ + { + u64 summand = (rem << 1) >= b_abs; + + res_abs += summand; + } + + res = (s64) res_abs; + if (a_neg ^ b_neg) + res = -res; + return res; +} + static inline s64 drm_fixp_exp(s64 x) { s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); |