| 20,6 → 20,7 |
|---|
| * OTHER DEALINGS IN THE SOFTWARE. |
| * |
| * Authors: Dave Airlie |
| * Christian Konig |
| */ |
| #ifndef DRM_FIXED_H |
| #define DRM_FIXED_H |
| 65,4 → 66,95 |
|---|
| tmp /= 2; |
| return lower_32_bits(tmp); |
| } |
| |
| #define DRM_FIXED_POINT 32 |
| #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) |
| |
| static inline s64 drm_int2fixp(int a) |
| { |
| return ((s64)a) << DRM_FIXED_POINT; |
| } |
| |
| static inline int drm_fixp2int(int64_t a) |
| { |
| return ((s64)a) >> DRM_FIXED_POINT; |
| } |
| |
| static inline unsigned drm_fixp_msbset(int64_t a) |
| { |
| unsigned shift, sign = (a >> 63) & 1; |
| |
| for (shift = 62; shift > 0; --shift) |
| if (((a >> shift) & 1) != sign) |
| return shift; |
| |
| return 0; |
| } |
| |
| static inline s64 drm_fixp_mul(s64 a, s64 b) |
| { |
| unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b); |
| s64 result; |
| |
| if (shift > 61) { |
| shift = shift - 61; |
| a >>= (shift >> 1) + (shift & 1); |
| b >>= shift >> 1; |
| } else |
| shift = 0; |
| |
| result = a * b; |
| |
| if (shift > DRM_FIXED_POINT) |
| return result << (shift - DRM_FIXED_POINT); |
| |
| if (shift < DRM_FIXED_POINT) |
| return result >> (DRM_FIXED_POINT - shift); |
| |
| return result; |
| } |
| |
| static inline s64 drm_fixp_div(s64 a, s64 b) |
| { |
| unsigned shift = 62 - drm_fixp_msbset(a); |
| s64 result; |
| |
| a <<= shift; |
| |
| if (shift < DRM_FIXED_POINT) |
| b >>= (DRM_FIXED_POINT - shift); |
| |
| result = div64_s64(a, b); |
| |
| if (shift > DRM_FIXED_POINT) |
| return result >> (shift - DRM_FIXED_POINT); |
| |
| return result; |
| } |
| |
| static inline s64 drm_fixp_exp(s64 x) |
| { |
| s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); |
| s64 sum = DRM_FIXED_ONE, term, y = x; |
| u64 count = 1; |
| |
| if (x < 0) |
| y = -1 * x; |
| |
| term = y; |
| |
| while (term >= tolerance) { |
| sum = sum + term; |
| count = count + 1; |
| term = drm_fixp_mul(term, div64_s64(y, count)); |
| } |
| |
| if (x < 0) |
| sum = drm_fixp_div(DRM_FIXED_ONE, sum); |
| |
| return sum; |
| } |
| |
| #endif |