Last change
on this file since 559 was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
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File size:
1.3 KB
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1 | /* ef_acosh.c -- float version of e_acosh.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 | |
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17 | #include "fdlibm.h" |
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18 | |
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19 | #ifdef __STDC__ |
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20 | static const float |
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21 | #else |
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22 | static float |
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23 | #endif |
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24 | one = 1.0, |
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25 | ln2 = 6.9314718246e-01; /* 0x3f317218 */ |
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26 | |
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27 | #ifdef __STDC__ |
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28 | float acoshf(float x) |
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29 | #else |
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30 | float acoshf(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; |
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35 | __int32_t hx; |
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36 | GET_FLOAT_WORD(hx,x); |
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37 | if(hx<0x3f800000) { /* x < 1 */ |
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38 | return (x-x)/(x-x); |
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39 | } else if(hx >=0x4d800000) { /* x > 2**28 */ |
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40 | if(hx >=0x7f800000) { /* x is inf of NaN */ |
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41 | return x+x; |
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42 | } else |
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43 | return logf(x)+ln2; /* acosh(huge)=log(2x) */ |
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44 | } else if (hx==0x3f800000) { |
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45 | return 0.0; /* acosh(1) = 0 */ |
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46 | } else if (hx > 0x40000000) { /* 2**28 > x > 2 */ |
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47 | t=x*x; |
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48 | return logf((float)2.0*x-one/(x+sqrtf(t-one))); |
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49 | } else { /* 1<x<2 */ |
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50 | t = x-one; |
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51 | return log1pf(t+sqrtf((float)2.0*t+t*t)); |
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52 | } |
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53 | } |
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