1 | |
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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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