| /* |
| * Copyright 2009 Red Hat Inc. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR |
| * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
| * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
| * OTHER DEALINGS IN THE SOFTWARE. |
| * |
| * Authors: Dave Airlie |
| * Christian König |
| */ |
| #ifndef DRM_FIXED_H |
| #define DRM_FIXED_H |
| |
| #include <linux/math64.h> |
| |
| typedef union dfixed { |
| u32 full; |
| } fixed20_12; |
| |
| |
| #define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */ |
| #define dfixed_const_half(A) (u32)(((A) << 12) + 2048) |
| #define dfixed_const_666(A) (u32)(((A) << 12) + 2731) |
| #define dfixed_const_8(A) (u32)(((A) << 12) + 3277) |
| #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12) |
| #define dfixed_init(A) { .full = dfixed_const((A)) } |
| #define dfixed_init_half(A) { .full = dfixed_const_half((A)) } |
| #define dfixed_trunc(A) ((A).full >> 12) |
| #define dfixed_frac(A) ((A).full & ((1 << 12) - 1)) |
| |
| static inline u32 dfixed_floor(fixed20_12 A) |
| { |
| u32 non_frac = dfixed_trunc(A); |
| |
| return dfixed_const(non_frac); |
| } |
| |
| static inline u32 dfixed_ceil(fixed20_12 A) |
| { |
| u32 non_frac = dfixed_trunc(A); |
| |
| if (A.full > dfixed_const(non_frac)) |
| return dfixed_const(non_frac + 1); |
| else |
| return dfixed_const(non_frac); |
| } |
| |
| static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) |
| { |
| u64 tmp = ((u64)A.full << 13); |
| |
| do_div(tmp, B.full); |
| tmp += 1; |
| 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) |
| #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(s64 a) |
| { |
| return ((s64)a) >> DRM_FIXED_POINT; |
| } |
| |
| 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; |
| |
| 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_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); |
| 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 |