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/*
* PSn00bSDK (incomplete) trigonometry library
* (C) 2019-2022 Lameguy64, spicyjpeg - MPL licensed
*
* Based on isin_S4 implementation from coranac:
* https://www.coranac.com/2009/07/sines
*/
#define qN_l 10
#define qN_h 15
#define qA 12
#define B 19900
#define C 3516
static inline int _isin(int qN, int x) {
int c, x2, y;
c = x << (30 - qN); // Semi-circle info into carry.
x -= 1 << qN; // sine -> cosine calc
x <<= (31 - qN); // Mask with PI
x >>= (31 - qN); // Note: SIGNED shift! (to qN)
x *= x;
x >>= (2 * qN - 14); // x=x^2 To Q14
y = B - (x * C >> 14); // B - x^2*C
y = (1 << qA) - (x * y >> 16); // A - x^2*(B-x^2*C)
return (c >= 0) ? y : (-y);
}
int isin(int x) {
return _isin(qN_l, x);
}
int icos(int x) {
return _isin(qN_l, x + (1 << qN_l));
}
int hisin(int x) {
return _isin(qN_h, x);
}
int hicos(int x) {
return _isin(qN_h, x + (1 << qN_h));
}
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