1 | /* origin: FreeBSD /usr/src/lib/msun/src/s_ctanhf.c */
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2 | /*-
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3 | * Copyright (c) 2011 David Schultz
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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 tangent of a complex argument z. See s_ctanh.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 | float complex ctanhf(float complex z)
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34 | {
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35 | float x, y;
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36 | float t, beta, s, rho, denom;
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37 | uint32_t hx, ix;
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38 |
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39 | x = crealf(z);
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40 | y = cimagf(z);
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41 |
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42 | GET_FLOAT_WORD(hx, x);
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43 | ix = hx & 0x7fffffff;
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44 |
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45 | if (ix >= 0x7f800000) {
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46 | if (ix & 0x7fffff)
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47 | return CMPLXF(x, (y == 0 ? y : x * y));
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48 | SET_FLOAT_WORD(x, hx - 0x40000000);
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49 | return CMPLXF(x, copysignf(0, isinf(y) ? y : sinf(y) * cosf(y)));
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50 | }
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51 |
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52 | if (!isfinite(y))
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53 | return CMPLXF(ix ? y - y : x, y - y);
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54 |
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55 | if (ix >= 0x41300000) { /* x >= 11 */
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56 | float exp_mx = expf(-fabsf(x));
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57 | return CMPLXF(copysignf(1, x), 4 * sinf(y) * cosf(y) * exp_mx * exp_mx);
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58 | }
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59 |
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60 | t = tanf(y);
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61 | beta = 1.0 + t * t;
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62 | s = sinhf(x);
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63 | rho = sqrtf(1 + s * s);
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64 | denom = 1 + beta * s * s;
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65 | return CMPLXF((beta * rho * s) / denom, t / denom);
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66 | }
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