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 | |