1 /* Copyright (c) 2013-2015 Jeffrey Pfau
2 *
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 #ifndef UTIL_MATH_H
7 #define UTIL_MATH_H
8
9 #include <mgba-util/common.h>
10
11 CXX_GUARD_START
12
popcount32(unsigned bits)13 static inline uint32_t popcount32(unsigned bits) {
14 bits = bits - ((bits >> 1) & 0x55555555);
15 bits = (bits & 0x33333333) + ((bits >> 2) & 0x33333333);
16 return (((bits + (bits >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
17 }
18
clz32(uint32_t bits)19 static inline unsigned clz32(uint32_t bits) {
20 #if defined(__GNUC__) || __clang__
21 if (!bits) {
22 return 32;
23 }
24 return __builtin_clz(bits);
25 #else
26 static const int table[256] = {
27 8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
28 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
29 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
30 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
31 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
32 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
33 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
34 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
35 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
36 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
37 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
38 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
39 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
40 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
41 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
42 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
43 };
44
45 if (bits & 0xFF000000) {
46 return table[bits >> 24];
47 } else if (bits & 0x00FF0000) {
48 return table[bits >> 16] + 8;
49 } else if (bits & 0x0000FF00) {
50 return table[bits >> 8] + 16;
51 }
52 return table[bits] + 24;
53 #endif
54 }
55
toPow2(uint32_t bits)56 static inline uint32_t toPow2(uint32_t bits) {
57 if (!bits) {
58 return 0;
59 }
60 unsigned lz = clz32(bits - 1);
61 return 1 << (32 - lz);
62 }
63
reduceFraction(int * num,int * den)64 static inline int reduceFraction(int* num, int* den) {
65 int n = *num;
66 int d = *den;
67 while (d != 0) {
68 int temp = n % d;
69 n = d;
70 d = temp;
71 }
72 *num /= n;
73 *den /= n;
74 return n;
75 }
76
77 #define TYPE_GENERICIZE(MACRO) \
78 MACRO(int, Int) \
79 MACRO(unsigned, UInt)
80
81 #define LOCK_ASPECT_RATIO(T, t) \
82 static inline void lockAspectRatio ## t(T refW, T refH, T* w, T* h) { \
83 if (*w * refH > *h * refW) { \
84 *w = *h * refW / refH; \
85 } else if (*w * refH < *h * refW) { \
86 *h = *w * refH / refW; \
87 } \
88 }
89
90 TYPE_GENERICIZE(LOCK_ASPECT_RATIO)
91 #undef LOCK_ASPECT_RATIO
92
93 #define LOCK_INTEGER_RATIO(T, t) \
94 static inline void lockIntegerRatio ## t(T ref, T* val) { \
95 if (*val >= ref) { \
96 *val -= *val % ref; \
97 } \
98 }
99
100 TYPE_GENERICIZE(LOCK_INTEGER_RATIO)
101 #undef LOCK_INTEGER_RATIO
102
103 #undef TYPE_GENERICIZE
104 CXX_GUARD_END
105
106 #endif
107