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| 2 | /* @(#)w_exp2.c 5.1 93/09/24 */ |
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| 3 | /* |
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| 4 | * ==================================================== |
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| 5 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 6 | * |
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| 7 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 8 | * Permission to use, copy, modify, and distribute this |
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| 9 | * software is freely granted, provided that this notice |
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| 10 | * is preserved. |
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| 11 | * ==================================================== |
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| 12 | */ |
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| 13 | |
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| 14 | /* |
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| 15 | FUNCTION |
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| 16 | <<exp2>>, <<exp2f>>---exponential, base 2 |
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| 17 | INDEX |
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| 18 | exp2 |
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| 19 | INDEX |
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| 20 | exp2f |
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| 21 | |
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| 22 | SYNOPSIS |
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| 23 | #include <math.h> |
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| 24 | double exp2(double <[x]>); |
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| 25 | float exp2f(float <[x]>); |
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| 26 | |
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| 27 | DESCRIPTION |
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| 28 | <<exp2>> and <<exp2f>> calculate 2 ^ <[x]>, that is, |
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| 29 | @ifnottex |
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| 30 | 2 raised to the power <[x]>. |
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| 31 | @end ifnottex |
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| 32 | @tex |
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| 33 | $2^x$ |
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| 34 | @end tex |
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| 35 | |
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| 36 | You can use the (non-ANSI) function <<matherr>> to specify |
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| 37 | error handling for these functions. |
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| 38 | |
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| 39 | RETURNS |
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| 40 | On success, <<exp2>> and <<exp2f>> return the calculated value. |
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| 41 | If the result underflows, the returned value is <<0>>. If the |
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| 42 | result overflows, the returned value is <<HUGE_VAL>>. In |
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| 43 | either case, <<errno>> is set to <<ERANGE>>. |
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| 44 | |
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| 45 | PORTABILITY |
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| 46 | ANSI C, POSIX. |
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| 47 | |
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| 48 | */ |
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| 49 | |
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| 50 | /* |
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| 51 | * wrapper exp2(x) |
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| 52 | */ |
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| 53 | |
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| 54 | #include "fdlibm.h" |
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| 55 | #include <errno.h> |
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| 56 | #include <math.h> |
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| 57 | |
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| 58 | #ifndef _DOUBLE_IS_32BITS |
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| 59 | |
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| 60 | #ifdef __STDC__ |
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| 61 | double exp2(double x) /* wrapper exp2 */ |
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| 62 | #else |
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| 63 | double exp2(x) /* wrapper exp2 */ |
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| 64 | double x; |
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| 65 | #endif |
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| 66 | { |
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| 67 | return pow(2.0, x); |
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| 68 | } |
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| 69 | |
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| 70 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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