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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | |
| 2 | /* |
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| 3 | * ==================================================== |
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| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 5 | * |
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| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 7 | * Permission to use, copy, modify, and distribute this |
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| 8 | * software is freely granted, provided that this notice |
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| 9 | * is preserved. |
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| 10 | * ==================================================== |
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| 11 | */ |
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| 12 | |||
| 13 | |||
| 14 | FUNCTION |
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| 15 | < |
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| 16 | INDEX |
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| 17 | sin |
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| 18 | INDEX |
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| 19 | sinf |
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| 20 | INDEX |
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| 21 | cos |
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| 22 | INDEX |
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| 23 | cosf |
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| 24 | ANSI_SYNOPSIS |
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| 25 | #include |
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| 26 | double sin(double <[x]>); |
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| 27 | float sinf(float <[x]>); |
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| 28 | double cos(double <[x]>); |
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| 29 | float cosf(float <[x]>); |
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| 30 | |||
| 31 | |||
| 32 | #include |
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| 33 | double sin(<[x]>) |
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| 34 | double <[x]>; |
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| 35 | float sinf(<[x]>) |
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| 36 | float <[x]>; |
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| 37 | |||
| 38 | |||
| 39 | double <[x]>; |
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| 40 | float cosf(<[x]>) |
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| 41 | float <[x]>; |
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| 42 | |||
| 43 | |||
| 44 | < |
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| 45 | of the argument <[x]>. Angles are specified in radians. |
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| 46 | |||
| 47 | |||
| 48 | return < |
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| 49 | |||
| 50 | |||
| 51 | |||
| 52 | The sine or cosine of <[x]> is returned. |
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| 53 | |||
| 54 | |||
| 55 | < |
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| 56 | < |
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| 57 | |||
| 58 | |||
| 59 | sin ansi pure |
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| 60 | sinf - pure |
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| 61 | */ |
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| 62 | |||
| 63 | |||
| 64 | * Return sine function of x. |
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| 65 | * |
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| 66 | * kernel function: |
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| 67 | * __kernel_sin ... sine function on [-pi/4,pi/4] |
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| 68 | * __kernel_cos ... cose function on [-pi/4,pi/4] |
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| 69 | * __ieee754_rem_pio2 ... argument reduction routine |
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| 70 | * |
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| 71 | * Method. |
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| 72 | * Let S,C and T denote the sin, cos and tan respectively on |
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| 73 | * [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2 |
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| 74 | * in [-pi/4 , +pi/4], and let n = k mod 4. |
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| 75 | * We have |
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| 76 | * |
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| 77 | * n sin(x) cos(x) tan(x) |
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| 78 | * ---------------------------------------------------------- |
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| 79 | * 0 S C T |
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| 80 | * 1 C -S -1/T |
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| 81 | * 2 -S -C T |
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| 82 | * 3 -C S -1/T |
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| 83 | * ---------------------------------------------------------- |
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| 84 | * |
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| 85 | * Special cases: |
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| 86 | * Let trig be any of sin, cos, or tan. |
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| 87 | * trig(+-INF) is NaN, with signals; |
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| 88 | * trig(NaN) is that NaN; |
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| 89 | * |
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| 90 | * Accuracy: |
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| 91 | * TRIG(x) returns trig(x) nearly rounded |
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| 92 | */ |
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| 93 | |||
| 94 | |||
| 95 | |||
| 96 | |||
| 97 | |||
| 98 | |||
| 99 | double sin(double x) |
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| 100 | #else |
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| 101 | double sin(x) |
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| 102 | double x; |
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| 103 | #endif |
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| 104 | { |
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| 105 | double y[2],z=0.0; |
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| 106 | __int32_t n,ix; |
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| 107 | |||
| 108 | |||
| 109 | GET_HIGH_WORD(ix,x); |
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| 110 | |||
| 111 | |||
| 112 | ix &= 0x7fffffff; |
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| 113 | if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0); |
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| 114 | |||
| 115 | |||
| 116 | else if (ix>=0x7ff00000) return x-x; |
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| 117 | |||
| 118 | |||
| 119 | else { |
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| 120 | n = __ieee754_rem_pio2(x,y); |
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| 121 | switch(n&3) { |
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| 122 | case 0: return __kernel_sin(y[0],y[1],1); |
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| 123 | case 1: return __kernel_cos(y[0],y[1]); |
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| 124 | case 2: return -__kernel_sin(y[0],y[1],1); |
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| 125 | default: |
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| 126 | return -__kernel_cos(y[0],y[1]); |
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| 127 | } |
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| 128 | } |
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| 129 | } |
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| 130 | |||
| 131 | |||
| 132 |