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1 //=========================================================================== |
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2 // |
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3 // w_exp.c |
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4 // |
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5 // Part of the standard mathematical function library |
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6 // |
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7 //=========================================================================== |
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8 //####COPYRIGHTBEGIN#### |
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9 // |
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10 // ------------------------------------------- |
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11 // The contents of this file are subject to the Cygnus eCos Public License |
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12 // Version 1.0 (the "License"); you may not use this file except in |
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13 // compliance with the License. You may obtain a copy of the License at |
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14 // http://sourceware.cygnus.com/ecos |
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15 // |
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16 // Software distributed under the License is distributed on an "AS IS" |
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17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the |
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18 // License for the specific language governing rights and limitations under |
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19 // the License. |
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20 // |
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21 // The Original Code is eCos - Embedded Cygnus Operating System, released |
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22 // September 30, 1998. |
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23 // |
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24 // The Initial Developer of the Original Code is Cygnus. Portions created |
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25 // by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions. All Rights Reserved. |
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26 // ------------------------------------------- |
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27 // |
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28 //####COPYRIGHTEND#### |
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29 //=========================================================================== |
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30 //#####DESCRIPTIONBEGIN#### |
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31 // |
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32 // Author(s): jlarmour |
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33 // Contributors: jlarmour |
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34 // Date: 1998-02-13 |
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35 // Purpose: |
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36 // Description: |
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37 // Usage: |
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38 // |
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39 //####DESCRIPTIONEND#### |
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40 // |
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41 //=========================================================================== |
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42 |
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43 // CONFIGURATION |
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44 |
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45 #include <pkgconf/libm.h> // Configuration header |
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46 |
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47 // Include the Math library? |
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48 #ifdef CYGPKG_LIBM |
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49 |
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50 // Derived from code with the following copyright |
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51 |
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52 |
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53 /* @(#)w_exp.c 1.3 95/01/18 */ |
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54 /* |
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55 * ==================================================== |
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56 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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57 * |
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58 * Developed at SunSoft, a Sun Microsystems, Inc. business. |
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59 * Permission to use, copy, modify, and distribute this |
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60 * software is freely granted, provided that this notice |
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61 * is preserved. |
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62 * ==================================================== |
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63 */ |
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64 |
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65 /* |
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66 * wrapper exp(x) |
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67 */ |
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68 |
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69 #include "mathincl/fdlibm.h" |
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70 |
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71 static const double |
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72 o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */ |
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73 u_threshold= -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */ |
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74 |
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75 double exp(double x) /* wrapper exp */ |
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76 { |
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77 #ifdef CYGSEM_LIBM_COMPAT_IEEE_ONLY |
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78 return __ieee754_exp(x); |
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79 #else |
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80 double z; |
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81 z = __ieee754_exp(x); |
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82 if(cyg_libm_get_compat_mode() == CYGNUM_LIBM_COMPAT_IEEE) return z; |
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83 if(finite(x)) { |
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84 if(x>o_threshold) |
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85 return __kernel_standard(x,x,6); /* exp overflow */ |
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86 else if(x<u_threshold) |
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87 return __kernel_standard(x,x,7); /* exp underflow */ |
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88 } |
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89 return z; |
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90 #endif |
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91 } |
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92 |
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93 #endif // ifdef CYGPKG_LIBM |
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94 |
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95 // EOF w_exp.c |
