1 /* 2 * Copyright 2009 Red Hat Inc. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be included in 12 * all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR 18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 20 * OTHER DEALINGS IN THE SOFTWARE. 21 * 22 * Authors: Dave Airlie 23 * Christian König 24 */ 25 #ifndef DRM_FIXED_H 26 #define DRM_FIXED_H 27 28 #include <linux/math64.h> 29 30 typedef union dfixed { 31 u32 full; 32 } fixed20_12; 33 34 35 #define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */ 36 #define dfixed_const_half(A) (u32)(((A) << 12) + 2048) 37 #define dfixed_const_666(A) (u32)(((A) << 12) + 2731) 38 #define dfixed_const_8(A) (u32)(((A) << 12) + 3277) 39 #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12) 40 #define dfixed_init(A) { .full = dfixed_const((A)) } 41 #define dfixed_init_half(A) { .full = dfixed_const_half((A)) } 42 #define dfixed_trunc(A) ((A).full >> 12) 43 #define dfixed_frac(A) ((A).full & ((1 << 12) - 1)) 44 45 static inline u32 dfixed_floor(fixed20_12 A) 46 { 47 u32 non_frac = dfixed_trunc(A); 48 49 return dfixed_const(non_frac); 50 } 51 52 static inline u32 dfixed_ceil(fixed20_12 A) 53 { 54 u32 non_frac = dfixed_trunc(A); 55 56 if (A.full > dfixed_const(non_frac)) 57 return dfixed_const(non_frac + 1); 58 else 59 return dfixed_const(non_frac); 60 } 61 62 static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) 63 { 64 u64 tmp = ((u64)A.full << 13); 65 66 do_div(tmp, B.full); 67 tmp += 1; 68 tmp /= 2; 69 return lower_32_bits(tmp); 70 } 71 72 #define DRM_FIXED_POINT 32 73 #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) 74 #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) 75 #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) 76 77 static inline s64 drm_int2fixp(int a) 78 { 79 return ((s64)a) << DRM_FIXED_POINT; 80 } 81 82 static inline int drm_fixp2int(int64_t a) 83 { 84 return ((s64)a) >> DRM_FIXED_POINT; 85 } 86 87 static inline unsigned drm_fixp_msbset(int64_t a) 88 { 89 unsigned shift, sign = (a >> 63) & 1; 90 91 for (shift = 62; shift > 0; --shift) 92 if (((a >> shift) & 1) != sign) 93 return shift; 94 95 return 0; 96 } 97 98 static inline s64 drm_fixp_mul(s64 a, s64 b) 99 { 100 unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b); 101 s64 result; 102 103 if (shift > 61) { 104 shift = shift - 61; 105 a >>= (shift >> 1) + (shift & 1); 106 b >>= shift >> 1; 107 } else 108 shift = 0; 109 110 result = a * b; 111 112 if (shift > DRM_FIXED_POINT) 113 return result << (shift - DRM_FIXED_POINT); 114 115 if (shift < DRM_FIXED_POINT) 116 return result >> (DRM_FIXED_POINT - shift); 117 118 return result; 119 } 120 121 static inline s64 drm_fixp_div(s64 a, s64 b) 122 { 123 unsigned shift = 62 - drm_fixp_msbset(a); 124 s64 result; 125 126 a <<= shift; 127 128 if (shift < DRM_FIXED_POINT) 129 b >>= (DRM_FIXED_POINT - shift); 130 131 result = div64_s64(a, b); 132 133 if (shift > DRM_FIXED_POINT) 134 return result >> (shift - DRM_FIXED_POINT); 135 136 return result; 137 } 138 139 static inline s64 drm_fixp_exp(s64 x) 140 { 141 s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); 142 s64 sum = DRM_FIXED_ONE, term, y = x; 143 u64 count = 1; 144 145 if (x < 0) 146 y = -1 * x; 147 148 term = y; 149 150 while (term >= tolerance) { 151 sum = sum + term; 152 count = count + 1; 153 term = drm_fixp_mul(term, div64_s64(y, count)); 154 } 155 156 if (x < 0) 157 sum = drm_fixp_div(DRM_FIXED_ONE, sum); 158 159 return sum; 160 } 161 162 #endif 163