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dcos.h
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1/*
2
3MIT License
4
5Copyright (c) 2021 PCSX-Redux authors
6
7Permission is hereby granted, free of charge, to any person obtaining a copy
8of this software and associated documentation files (the "Software"), to deal
9in the Software without restriction, including without limitation the rights
10to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11copies of the Software, and to permit persons to whom the Software is
12furnished to do so, subject to the following conditions:
13
14The above copyright notice and this permission notice shall be included in all
15copies or substantial portions of the Software.
16
17THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
20AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23SOFTWARE.
24
25*/
26
27#pragma once
28
29#include <stdint.h>
30
31// 2kB
32extern int32_t g_cosTable[512];
33static const unsigned int DC_2PI = 2048;
34static const unsigned int DC_PI = 1024;
35static const unsigned int DC_PI2 = 512;
36static const unsigned int DC_PI4 = 256;
37
38static inline int32_t dCos(unsigned int t) {
39 t %= DC_2PI;
40 int32_t r;
41
42 if (t < DC_PI2) {
43 r = g_cosTable[t];
44 } else if (t < DC_PI) {
45 r = -g_cosTable[DC_PI - 1 - t];
46 } else if (t < (DC_PI + DC_PI2)) {
47 r = -g_cosTable[t - DC_PI];
48 } else {
49 r = g_cosTable[DC_2PI - 1 - t];
50 }
51
52 return r;
53}
54
55// sin(x) = cos(x - pi / 2)
56static inline int32_t dSin(unsigned int t) {
57 t %= DC_2PI;
58
59 if (t < DC_PI2) return dCos(t + DC_2PI - DC_PI2);
60 return dCos(t - DC_PI2);
61}
62
63void generateCosTable();
uint32_t t
Definition cop0.c:79
uint32_t r
Definition cpu.c:222
int32_t g_cosTable[512]
Definition dcos.c:32
void generateCosTable()
Definition dcos.c:34