1 | /* sf_asinh.c -- float version of s_asinh.c. |
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2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
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3 | */ |
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4 | |
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5 | /* |
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6 | * ==================================================== |
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7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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8 | * |
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9 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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10 | * Permission to use, copy, modify, and distribute this |
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11 | * software is freely granted, provided that this notice |
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12 | * is preserved. |
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13 | * ==================================================== |
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14 | */ |
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15 | |
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16 | #include "fdlibm.h" |
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17 | |
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18 | #ifdef __STDC__ |
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19 | static const float |
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20 | #else |
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21 | static float |
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22 | #endif |
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23 | one = 1.0000000000e+00, /* 0x3F800000 */ |
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24 | ln2 = 6.9314718246e-01, /* 0x3f317218 */ |
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25 | huge= 1.0000000000e+30; |
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26 | |
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27 | #ifdef __STDC__ |
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28 | float asinhf(float x) |
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29 | #else |
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30 | float asinhf(x) |
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31 | float x; |
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32 | #endif |
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33 | { |
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34 | float t,w; |
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35 | __int32_t hx,ix; |
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36 | GET_FLOAT_WORD(hx,x); |
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37 | ix = hx&0x7fffffff; |
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38 | if(ix>=0x7f800000) return x+x; /* x is inf or NaN */ |
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39 | if(ix< 0x31800000) { /* |x|<2**-28 */ |
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40 | if(huge+x>one) return x; /* return x inexact except 0 */ |
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41 | } |
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42 | if(ix>0x4d800000) { /* |x| > 2**28 */ |
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43 | w = logf(fabsf(x))+ln2; |
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44 | } else if (ix>0x40000000) { /* 2**28 > |x| > 2.0 */ |
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45 | t = fabsf(x); |
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46 | w = logf((float)2.0*t+one/(sqrtf(x*x+one)+t)); |
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47 | } else { /* 2.0 > |x| > 2**-28 */ |
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48 | t = x*x; |
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49 | w =log1pf(fabsf(x)+t/(one+sqrtf(one+t))); |
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50 | } |
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51 | if(hx>0) return w; else return -w; |
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52 | } |
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53 | |
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54 | #ifdef _DOUBLE_IS_32BITS |
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55 | |
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56 | #ifdef __STDC__ |
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57 | double asinh(double x) |
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58 | #else |
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59 | double asinh(x) |
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60 | double x; |
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61 | #endif |
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62 | { |
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63 | return (double) asinhf((float) x); |
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64 | } |
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65 | |
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66 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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