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771fe6b9 JG |
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 | |
210a0b9e | 23 | * Christian König |
771fe6b9 | 24 | */ |
68adac5e BS |
25 | #ifndef DRM_FIXED_H |
26 | #define DRM_FIXED_H | |
771fe6b9 | 27 | |
cde3d37b | 28 | #include <linux/kernel.h> |
210a0b9e AD |
29 | #include <linux/math64.h> |
30 | ||
68adac5e | 31 | typedef union dfixed { |
771fe6b9 JG |
32 | u32 full; |
33 | } fixed20_12; | |
34 | ||
35 | ||
68adac5e BS |
36 | #define dfixed_const(A) (u32)(((A) << 12))/* + ((B + 0.000122)*4096)) */ |
37 | #define dfixed_const_half(A) (u32)(((A) << 12) + 2048) | |
38 | #define dfixed_const_666(A) (u32)(((A) << 12) + 2731) | |
39 | #define dfixed_const_8(A) (u32)(((A) << 12) + 3277) | |
40 | #define dfixed_mul(A, B) ((u64)((u64)(A).full * (B).full + 2048) >> 12) | |
41 | #define dfixed_init(A) { .full = dfixed_const((A)) } | |
42 | #define dfixed_init_half(A) { .full = dfixed_const_half((A)) } | |
43 | #define dfixed_trunc(A) ((A).full >> 12) | |
f7f6c340 | 44 | #define dfixed_frac(A) ((A).full & ((1 << 12) - 1)) |
771fe6b9 | 45 | |
68adac5e | 46 | static inline u32 dfixed_floor(fixed20_12 A) |
69b3b5e5 | 47 | { |
68adac5e | 48 | u32 non_frac = dfixed_trunc(A); |
69b3b5e5 | 49 | |
68adac5e | 50 | return dfixed_const(non_frac); |
69b3b5e5 AD |
51 | } |
52 | ||
68adac5e | 53 | static inline u32 dfixed_ceil(fixed20_12 A) |
69b3b5e5 | 54 | { |
68adac5e | 55 | u32 non_frac = dfixed_trunc(A); |
69b3b5e5 | 56 | |
68adac5e BS |
57 | if (A.full > dfixed_const(non_frac)) |
58 | return dfixed_const(non_frac + 1); | |
69b3b5e5 | 59 | else |
68adac5e | 60 | return dfixed_const(non_frac); |
69b3b5e5 AD |
61 | } |
62 | ||
68adac5e | 63 | static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B) |
771fe6b9 JG |
64 | { |
65 | u64 tmp = ((u64)A.full << 13); | |
66 | ||
67 | do_div(tmp, B.full); | |
68 | tmp += 1; | |
69 | tmp /= 2; | |
70 | return lower_32_bits(tmp); | |
71 | } | |
210a0b9e AD |
72 | |
73 | #define DRM_FIXED_POINT 32 | |
8b253208 | 74 | #define DRM_FIXED_POINT_HALF 16 |
210a0b9e AD |
75 | #define DRM_FIXED_ONE (1ULL << DRM_FIXED_POINT) |
76 | #define DRM_FIXED_DECIMAL_MASK (DRM_FIXED_ONE - 1) | |
77 | #define DRM_FIXED_DIGITS_MASK (~DRM_FIXED_DECIMAL_MASK) | |
64566b5e HW |
78 | #define DRM_FIXED_EPSILON 1LL |
79 | #define DRM_FIXED_ALMOST_ONE (DRM_FIXED_ONE - DRM_FIXED_EPSILON) | |
210a0b9e AD |
80 | |
81 | static inline s64 drm_int2fixp(int a) | |
82 | { | |
83 | return ((s64)a) << DRM_FIXED_POINT; | |
84 | } | |
85 | ||
64566b5e | 86 | static inline int drm_fixp2int(s64 a) |
210a0b9e AD |
87 | { |
88 | return ((s64)a) >> DRM_FIXED_POINT; | |
89 | } | |
90 | ||
8b253208 MC |
91 | static inline int drm_fixp2int_round(s64 a) |
92 | { | |
93 | return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1))); | |
94 | } | |
95 | ||
64566b5e HW |
96 | static inline int drm_fixp2int_ceil(s64 a) |
97 | { | |
98 | if (a > 0) | |
99 | return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE); | |
100 | else | |
101 | return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE); | |
102 | } | |
103 | ||
104 | static inline unsigned drm_fixp_msbset(s64 a) | |
210a0b9e AD |
105 | { |
106 | unsigned shift, sign = (a >> 63) & 1; | |
107 | ||
108 | for (shift = 62; shift > 0; --shift) | |
a838834b | 109 | if (((a >> shift) & 1) != sign) |
210a0b9e AD |
110 | return shift; |
111 | ||
112 | return 0; | |
113 | } | |
114 | ||
115 | static inline s64 drm_fixp_mul(s64 a, s64 b) | |
116 | { | |
117 | unsigned shift = drm_fixp_msbset(a) + drm_fixp_msbset(b); | |
118 | s64 result; | |
119 | ||
a838834b AD |
120 | if (shift > 61) { |
121 | shift = shift - 61; | |
122 | a >>= (shift >> 1) + (shift & 1); | |
210a0b9e AD |
123 | b >>= shift >> 1; |
124 | } else | |
125 | shift = 0; | |
126 | ||
127 | result = a * b; | |
128 | ||
129 | if (shift > DRM_FIXED_POINT) | |
130 | return result << (shift - DRM_FIXED_POINT); | |
131 | ||
132 | if (shift < DRM_FIXED_POINT) | |
133 | return result >> (DRM_FIXED_POINT - shift); | |
134 | ||
135 | return result; | |
136 | } | |
137 | ||
138 | static inline s64 drm_fixp_div(s64 a, s64 b) | |
139 | { | |
a838834b | 140 | unsigned shift = 62 - drm_fixp_msbset(a); |
210a0b9e AD |
141 | s64 result; |
142 | ||
143 | a <<= shift; | |
144 | ||
145 | if (shift < DRM_FIXED_POINT) | |
146 | b >>= (DRM_FIXED_POINT - shift); | |
147 | ||
148 | result = div64_s64(a, b); | |
149 | ||
150 | if (shift > DRM_FIXED_POINT) | |
151 | return result >> (shift - DRM_FIXED_POINT); | |
152 | ||
153 | return result; | |
154 | } | |
155 | ||
64566b5e HW |
156 | static inline s64 drm_fixp_from_fraction(s64 a, s64 b) |
157 | { | |
158 | s64 res; | |
159 | bool a_neg = a < 0; | |
160 | bool b_neg = b < 0; | |
161 | u64 a_abs = a_neg ? -a : a; | |
162 | u64 b_abs = b_neg ? -b : b; | |
163 | u64 rem; | |
164 | ||
165 | /* determine integer part */ | |
166 | u64 res_abs = div64_u64_rem(a_abs, b_abs, &rem); | |
167 | ||
168 | /* determine fractional part */ | |
169 | { | |
170 | u32 i = DRM_FIXED_POINT; | |
171 | ||
172 | do { | |
173 | rem <<= 1; | |
174 | res_abs <<= 1; | |
175 | if (rem >= b_abs) { | |
176 | res_abs |= 1; | |
177 | rem -= b_abs; | |
178 | } | |
179 | } while (--i != 0); | |
180 | } | |
181 | ||
182 | /* round up LSB */ | |
183 | { | |
184 | u64 summand = (rem << 1) >= b_abs; | |
185 | ||
186 | res_abs += summand; | |
187 | } | |
188 | ||
189 | res = (s64) res_abs; | |
190 | if (a_neg ^ b_neg) | |
191 | res = -res; | |
192 | return res; | |
193 | } | |
194 | ||
210a0b9e AD |
195 | static inline s64 drm_fixp_exp(s64 x) |
196 | { | |
197 | s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000); | |
198 | s64 sum = DRM_FIXED_ONE, term, y = x; | |
199 | u64 count = 1; | |
200 | ||
201 | if (x < 0) | |
202 | y = -1 * x; | |
203 | ||
204 | term = y; | |
205 | ||
206 | while (term >= tolerance) { | |
207 | sum = sum + term; | |
208 | count = count + 1; | |
209 | term = drm_fixp_mul(term, div64_s64(y, count)); | |
210 | } | |
211 | ||
212 | if (x < 0) | |
a838834b | 213 | sum = drm_fixp_div(DRM_FIXED_ONE, sum); |
210a0b9e AD |
214 | |
215 | return sum; | |
216 | } | |
217 | ||
771fe6b9 | 218 | #endif |