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| author | 3gg <3gg@shellblade.net> | 2025-12-27 12:03:39 -0800 |
|---|---|---|
| committer | 3gg <3gg@shellblade.net> | 2025-12-27 12:03:39 -0800 |
| commit | 5a079a2d114f96d4847d1ee305d5b7c16eeec50e (patch) | |
| tree | 8926ab44f168acf787d8e19608857b3af0f82758 /contrib/SDL-3.2.8/src/libm/s_sin.c | |
Initial commit
Diffstat (limited to 'contrib/SDL-3.2.8/src/libm/s_sin.c')
| -rw-r--r-- | contrib/SDL-3.2.8/src/libm/s_sin.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/contrib/SDL-3.2.8/src/libm/s_sin.c b/contrib/SDL-3.2.8/src/libm/s_sin.c new file mode 100644 index 0000000..511bc21 --- /dev/null +++ b/contrib/SDL-3.2.8/src/libm/s_sin.c | |||
| @@ -0,0 +1,74 @@ | |||
| 1 | #include "SDL_internal.h" | ||
| 2 | /* | ||
| 3 | * ==================================================== | ||
| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | ||
| 5 | * | ||
| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. | ||
| 7 | * Permission to use, copy, modify, and distribute this | ||
| 8 | * software is freely granted, provided that this notice | ||
| 9 | * is preserved. | ||
| 10 | * ==================================================== | ||
| 11 | */ | ||
| 12 | |||
| 13 | /* sin(x) | ||
| 14 | * Return sine function of x. | ||
| 15 | * | ||
| 16 | * kernel function: | ||
| 17 | * __kernel_sin ... sine function on [-pi/4,pi/4] | ||
| 18 | * __kernel_cos ... cose function on [-pi/4,pi/4] | ||
| 19 | * __ieee754_rem_pio2 ... argument reduction routine | ||
| 20 | * | ||
| 21 | * Method. | ||
| 22 | * Let S,C and T denote the sin, cos and tan respectively on | ||
| 23 | * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 | ||
| 24 | * in [-pi/4 , +pi/4], and let n = k mod 4. | ||
| 25 | * We have | ||
| 26 | * | ||
| 27 | * n sin(x) cos(x) tan(x) | ||
| 28 | * ---------------------------------------------------------- | ||
| 29 | * 0 S C T | ||
| 30 | * 1 C -S -1/T | ||
| 31 | * 2 -S -C T | ||
| 32 | * 3 -C S -1/T | ||
| 33 | * ---------------------------------------------------------- | ||
| 34 | * | ||
| 35 | * Special cases: | ||
| 36 | * Let trig be any of sin, cos, or tan. | ||
| 37 | * trig(+-INF) is NaN, with signals; | ||
| 38 | * trig(NaN) is that NaN; | ||
| 39 | * | ||
| 40 | * Accuracy: | ||
| 41 | * TRIG(x) returns trig(x) nearly rounded | ||
| 42 | */ | ||
| 43 | |||
| 44 | #include "math_libm.h" | ||
| 45 | #include "math_private.h" | ||
| 46 | |||
| 47 | double sin(double x) | ||
| 48 | { | ||
| 49 | double y[2],z=0.0; | ||
| 50 | int32_t n, ix; | ||
| 51 | |||
| 52 | /* High word of x. */ | ||
| 53 | GET_HIGH_WORD(ix,x); | ||
| 54 | |||
| 55 | /* |x| ~< pi/4 */ | ||
| 56 | ix &= 0x7fffffff; | ||
| 57 | if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0); | ||
| 58 | |||
| 59 | /* sin(Inf or NaN) is NaN */ | ||
| 60 | else if (ix>=0x7ff00000) return x-x; | ||
| 61 | |||
| 62 | /* argument reduction needed */ | ||
| 63 | else { | ||
| 64 | n = __ieee754_rem_pio2(x,y); | ||
| 65 | switch(n&3) { | ||
| 66 | case 0: return __kernel_sin(y[0],y[1],1); | ||
| 67 | case 1: return __kernel_cos(y[0],y[1]); | ||
| 68 | case 2: return -__kernel_sin(y[0],y[1],1); | ||
| 69 | default: | ||
| 70 | return -__kernel_cos(y[0],y[1]); | ||
| 71 | } | ||
| 72 | } | ||
| 73 | } | ||
| 74 | libm_hidden_def(sin) | ||
