1 | /* origin: FreeBSD /usr/src/lib/msun/src/s_ccoshf.c */
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2 | /*-
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3 | * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl
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4 | * All rights reserved.
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5 | *
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6 | * Redistribution and use in source and binary forms, with or without
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7 | * modification, are permitted provided that the following conditions
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8 | * are met:
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9 | * 1. Redistributions of source code must retain the above copyright
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10 | * notice unmodified, this list of conditions, and the following
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11 | * disclaimer.
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12 | * 2. Redistributions in binary form must reproduce the above copyright
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13 | * notice, this list of conditions and the following disclaimer in the
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14 | * documentation and/or other materials provided with the distribution.
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15 | *
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16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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26 | */
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27 | /*
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28 | * Hyperbolic cosine of a complex argument. See s_ccosh.c for details.
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29 | */
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30 |
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31 | #include "libm.h"
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32 |
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33 | static const float huge = 0x1p127;
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34 |
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35 | float complex ccoshf(float complex z)
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36 | {
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37 | float x, y, h;
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38 | int32_t hx, hy, ix, iy;
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39 |
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40 | x = crealf(z);
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41 | y = cimagf(z);
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42 |
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43 | GET_FLOAT_WORD(hx, x);
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44 | GET_FLOAT_WORD(hy, y);
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45 |
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46 | ix = 0x7fffffff & hx;
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47 | iy = 0x7fffffff & hy;
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48 |
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49 | if (ix < 0x7f800000 && iy < 0x7f800000) {
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50 | if (iy == 0)
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51 | return CMPLXF(coshf(x), x * y);
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52 | if (ix < 0x41100000) /* small x: normal case */
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53 | return CMPLXF(coshf(x) * cosf(y), sinhf(x) * sinf(y));
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54 |
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55 | /* |x| >= 9, so cosh(x) ~= exp(|x|) */
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56 | if (ix < 0x42b17218) {
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57 | /* x < 88.7: expf(|x|) won't overflow */
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58 | h = expf(fabsf(x)) * 0.5f;
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59 | return CMPLXF(h * cosf(y), copysignf(h, x) * sinf(y));
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60 | } else if (ix < 0x4340b1e7) {
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61 | /* x < 192.7: scale to avoid overflow */
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62 | z = __ldexp_cexpf(CMPLXF(fabsf(x), y), -1);
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63 | return CMPLXF(crealf(z), cimagf(z) * copysignf(1, x));
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64 | } else {
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65 | /* x >= 192.7: the result always overflows */
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66 | h = huge * x;
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67 | return CMPLXF(h * h * cosf(y), h * sinf(y));
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68 | }
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69 | }
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70 |
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71 | if (ix == 0 && iy >= 0x7f800000)
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72 | return CMPLXF(y - y, copysignf(0, x * (y - y)));
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73 |
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74 | if (iy == 0 && ix >= 0x7f800000) {
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75 | if ((hx & 0x7fffff) == 0)
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76 | return CMPLXF(x * x, copysignf(0, x) * y);
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77 | return CMPLXF(x * x, copysignf(0, (x + x) * y));
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78 | }
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79 |
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80 | if (ix < 0x7f800000 && iy >= 0x7f800000)
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81 | return CMPLXF(y - y, x * (y - y));
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82 |
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83 | if (ix >= 0x7f800000 && (hx & 0x7fffff) == 0) {
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84 | if (iy >= 0x7f800000)
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85 | return CMPLXF(x * x, x * (y - y));
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86 | return CMPLXF((x * x) * cosf(y), x * sinf(y));
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87 | }
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88 |
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89 | return CMPLXF((x * x) * (y - y), (x + x) * (y - y));
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90 | }
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