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4103 | Serge | 1 | /* |
2 | * Copyright 2009 Red Hat Inc. |
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3 | * |
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4 | * Permission is hereby granted, free of charge, to any person obtaining a |
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5 | * copy of this software and associated documentation files (the "Software"), |
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6 | * to deal in the Software without restriction, including without limitation |
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7 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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8 | * and/or sell copies of the Software, and to permit persons to whom the |
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9 | * Software is furnished to do so, subject to the following conditions: |
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10 | * |
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11 | * The above copyright notice and this permission notice shall be included in |
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12 | * all copies or substantial portions of the Software. |
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13 | * |
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14 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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15 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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16 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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17 | * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR |
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18 | * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
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19 | * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
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20 | * OTHER DEALINGS IN THE SOFTWARE. |
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21 | * |
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22 | * Authors: Dave Airlie |
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23 | * Christian König |
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24 | */ |
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25 | #ifndef DRM_FIXED_H |
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26 | #define DRM_FIXED_H |
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27 | |||
28 | #include |
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29 | |||
30 | typedef union dfixed { |
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31 | u32 full; |
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32 | } fixed20_12; |
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33 | |||
34 | |||
35 | #define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */ |
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36 | #define dfixed_const_half(A) (u32)(((A) << 12) + 2048) |
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37 | #define dfixed_const_666(A) (u32)(((A) << 12) + 2731) |
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38 | #define dfixed_const_8(A) (u32)(((A) << 12) + 3277) |
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39 | #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12) |
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40 | #define dfixed_init(A) { .full = dfixed_const((A)) } |
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41 | #define dfixed_init_half(A) { .full = dfixed_const_half((A)) } |
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42 | #define dfixed_trunc(A) ((A).full >> 12) |
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43 | #define dfixed_frac(A) ((A).full & ((1 << 12) - 1)) |
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44 | |||
45 | static inline u32 dfixed_floor(fixed20_12 A) |
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46 | { |
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47 | u32 non_frac = dfixed_trunc(A); |
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48 | |||
49 | return dfixed_const(non_frac); |
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50 | } |
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51 | |||
52 | static inline u32 dfixed_ceil(fixed20_12 A) |
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53 | { |
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54 | u32 non_frac = dfixed_trunc(A); |
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55 | |||
56 | if (A.full > dfixed_const(non_frac)) |
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57 | return dfixed_const(non_frac + 1); |
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58 | else |
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59 | return dfixed_const(non_frac); |
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60 | } |
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61 | |||
62 | static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) |
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63 | { |
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64 | u64 tmp = ((u64)A.full << 13); |
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65 | |||
66 | do_div(tmp, B.full); |
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67 | tmp += 1; |
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68 | tmp /= 2; |
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69 | return lower_32_bits(tmp); |
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70 | } |
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71 | |||
72 | #define DRM_FIXED_POINT 32 |
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73 | #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) |
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74 | #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) |
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75 | #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) |
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76 | |||
77 | static inline s64 drm_int2fixp(int a) |
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78 | { |
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79 | return ((s64)a) << DRM_FIXED_POINT; |
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80 | } |
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81 | |||
82 | static inline int drm_fixp2int(int64_t a) |
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83 | { |
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84 | return ((s64)a) >> DRM_FIXED_POINT; |
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85 | } |
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86 | |||
87 | static inline unsigned drm_fixp_msbset(int64_t a) |
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88 | { |
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89 | unsigned shift, sign = (a >> 63) & 1; |
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90 | |||
91 | for (shift = 62; shift > 0; --shift) |
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92 | if (((a >> shift) & 1) != sign) |
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93 | return shift; |
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94 | |||
95 | return 0; |
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96 | } |
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97 | |||
98 | static inline s64 drm_fixp_mul(s64 a, s64 b) |
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99 | { |
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100 | unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b); |
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101 | s64 result; |
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102 | |||
103 | if (shift > 61) { |
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104 | shift = shift - 61; |
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105 | a >>= (shift >> 1) + (shift & 1); |
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106 | b >>= shift >> 1; |
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107 | } else |
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108 | shift = 0; |
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109 | |||
110 | result = a * b; |
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111 | |||
112 | if (shift > DRM_FIXED_POINT) |
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113 | return result << (shift - DRM_FIXED_POINT); |
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114 | |||
115 | if (shift < DRM_FIXED_POINT) |
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116 | return result >> (DRM_FIXED_POINT - shift); |
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117 | |||
118 | return result; |
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119 | } |
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120 | |||
121 | static inline s64 drm_fixp_div(s64 a, s64 b) |
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122 | { |
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123 | unsigned shift = 62 - drm_fixp_msbset(a); |
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124 | s64 result; |
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125 | |||
126 | a <<= shift; |
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127 | |||
128 | if (shift < DRM_FIXED_POINT) |
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129 | b >>= (DRM_FIXED_POINT - shift); |
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130 | |||
131 | result = div64_s64(a, b); |
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132 | |||
133 | if (shift > DRM_FIXED_POINT) |
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134 | return result >> (shift - DRM_FIXED_POINT); |
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135 | |||
136 | return result; |
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137 | } |
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138 | |||
139 | static inline s64 drm_fixp_exp(s64 x) |
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140 | { |
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141 | s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); |
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142 | s64 sum = DRM_FIXED_ONE, term, y = x; |
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143 | u64 count = 1; |
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144 | |||
145 | if (x < 0) |
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146 | y = -1 * x; |
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147 | |||
148 | term = y; |
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149 | |||
150 | while (term >= tolerance) { |
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151 | sum = sum + term; |
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152 | count = count + 1; |
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153 | term = drm_fixp_mul(term, div64_s64(y, count)); |
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154 | } |
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155 | |||
156 | if (x < 0) |
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157 | sum = drm_fixp_div(DRM_FIXED_ONE, sum); |
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158 | |||
159 | return sum; |
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160 | } |
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161 | |||
162 | #endif>>>=><=>>><>><>><>><>><>><>><>><>><> |