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| Rev | Author | Line No. | Line |
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| 3362 | Serge | 1 | |
| 2 | /* |
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| 3 | * ==================================================== |
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| 4 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 5 | * |
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| 6 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 7 | * Permission to use, copy, modify, and distribute this |
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| 8 | * software is freely granted, provided that this notice |
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| 9 | * is preserved. |
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| 10 | * ==================================================== |
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| 11 | */ |
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| 12 | |||
| 13 | |||
| 14 | FUNCTION |
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| 15 | < |
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| 16 | INDEX |
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| 17 | exp |
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| 18 | INDEX |
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| 19 | expf |
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| 20 | |||
| 21 | |||
| 22 | #include |
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| 23 | double exp(double <[x]>); |
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| 24 | float expf(float <[x]>); |
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| 25 | |||
| 26 | |||
| 27 | #include |
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| 28 | double exp(<[x]>); |
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| 29 | double <[x]>; |
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| 30 | |||
| 31 | |||
| 32 | float <[x]>; |
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| 33 | |||
| 34 | |||
| 35 | < |
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| 36 | @ifnottex |
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| 37 | e raised to the power <[x]> (where e |
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| 38 | @end ifnottex |
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| 39 | @tex |
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| 40 | $e^x$ (where $e$ |
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| 41 | @end tex |
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| 42 | is the base of the natural system of logarithms, approximately 2.71828). |
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| 43 | |||
| 44 | |||
| 45 | error handling for these functions. |
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| 46 | |||
| 47 | |||
| 48 | On success, < |
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| 49 | If the result underflows, the returned value is <<0>>. If the |
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| 50 | result overflows, the returned value is < |
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| 51 | either case, < |
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| 52 | |||
| 53 | |||
| 54 | < |
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| 55 | |||
| 56 | |||
| 57 | |||
| 58 | |||
| 59 | * wrapper exp(x) |
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| 60 | */ |
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| 61 | |||
| 62 | |||
| 63 | #include |
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| 64 | |||
| 65 | |||
| 66 | |||
| 67 | |||
| 68 | static const double |
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| 69 | #else |
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| 70 | static double |
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| 71 | #endif |
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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 | |||
| 75 | |||
| 76 | double exp(double x) /* wrapper exp */ |
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| 77 | #else |
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| 78 | double exp(x) /* wrapper exp */ |
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| 79 | double x; |
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| 80 | #endif |
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| 81 | { |
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| 82 | #ifdef _IEEE_LIBM |
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| 83 | return __ieee754_exp(x); |
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| 84 | #else |
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| 85 | double z; |
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| 86 | struct exception exc; |
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| 87 | z = __ieee754_exp(x); |
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| 88 | if(_LIB_VERSION == _IEEE_) return z; |
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| 89 | if(finite(x)) { |
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| 90 | if(x>o_threshold) { |
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| 91 | /* exp(finite) overflow */ |
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| 92 | #ifndef HUGE_VAL |
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| 93 | #define HUGE_VAL inf |
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| 94 | double inf = 0.0; |
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| 95 | |||
| 96 | |||
| 97 | #endif |
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| 98 | exc.type = OVERFLOW; |
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| 99 | exc.name = "exp"; |
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| 100 | exc.err = 0; |
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| 101 | exc.arg1 = exc.arg2 = x; |
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| 102 | if (_LIB_VERSION == _SVID_) |
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| 103 | exc.retval = HUGE; |
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| 104 | else |
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| 105 | exc.retval = HUGE_VAL; |
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| 106 | if (_LIB_VERSION == _POSIX_) |
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| 107 | errno = ERANGE; |
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| 108 | else if (!matherr(&exc)) { |
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| 109 | errno = ERANGE; |
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| 110 | } |
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| 111 | if (exc.err != 0) |
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| 112 | errno = exc.err; |
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| 113 | return exc.retval; |
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| 114 | } else if(x |
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| 115 | /* exp(finite) underflow */ |
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| 116 | exc.type = UNDERFLOW; |
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| 117 | exc.name = "exp"; |
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| 118 | exc.err = 0; |
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| 119 | exc.arg1 = exc.arg2 = x; |
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| 120 | exc.retval = 0.0; |
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| 121 | if (_LIB_VERSION == _POSIX_) |
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| 122 | errno = ERANGE; |
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| 123 | else if (!matherr(&exc)) { |
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| 124 | errno = ERANGE; |
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| 125 | } |
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| 126 | if (exc.err != 0) |
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| 127 | errno = exc.err; |
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| 128 | return exc.retval; |
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| 129 | } |
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| 130 | } |
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| 131 | return z; |
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| 132 | #endif |
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| 133 | } |
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| 134 | |||
| 135 | |||
| 136 |