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| 2 | /* @(#)w_asin.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 | /* |
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| 16 | FUNCTION |
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| 17 | <<asin>>, <<asinf>>---arc sine |
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| 18 | |
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| 19 | INDEX |
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| 20 | asin |
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| 21 | INDEX |
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| 22 | asinf |
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| 23 | |
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| 24 | SYNOPSIS |
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| 25 | #include <math.h> |
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| 26 | double asin(double <[x]>); |
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| 27 | float asinf(float <[x]>); |
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| 28 | |
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| 29 | DESCRIPTION |
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| 30 | |
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| 31 | <<asin>> computes the inverse sine (arc sine) of the argument <[x]>. |
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| 32 | Arguments to <<asin>> must be in the range @minus{}1 to 1. |
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| 33 | |
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| 34 | <<asinf>> is identical to <<asin>>, other than taking and |
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| 35 | returning floats. |
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| 36 | |
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| 37 | You can modify error handling for these routines using <<matherr>>. |
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| 38 | |
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| 39 | RETURNS |
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| 40 | @ifnottex |
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| 41 | <<asin>> returns values in radians, in the range of -pi/2 to pi/2. |
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| 42 | @end ifnottex |
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| 43 | @tex |
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| 44 | <<asin>> returns values in radians, in the range of $-\pi/2$ to $\pi/2$. |
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| 45 | @end tex |
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| 46 | |
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| 47 | If <[x]> is not in the range @minus{}1 to 1, <<asin>> and <<asinf>> |
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| 48 | return NaN (not a number), set the global variable <<errno>> to |
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| 49 | <<EDOM>>, and issue a <<DOMAIN error>> message. |
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| 50 | |
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| 51 | You can change this error treatment using <<matherr>>. |
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| 52 | |
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| 53 | QUICKREF |
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| 54 | ansi svid posix rentrant |
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| 55 | asin y,y,y,m |
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| 56 | asinf n,n,n,m |
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| 57 | |
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| 58 | MATHREF |
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| 59 | asin, -1<=arg<=1, asin(arg),,, |
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| 60 | asin, NAN, arg,EDOM, DOMAIN |
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| 61 | |
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| 62 | MATHREF |
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| 63 | asinf, -1<=arg<=1, asin(arg),,, |
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| 64 | asinf, NAN, arg,EDOM, DOMAIN |
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| 65 | |
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| 66 | |
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| 67 | */ |
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| 68 | |
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| 69 | /* |
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| 70 | * wrapper asin(x) |
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| 71 | */ |
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| 72 | |
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| 73 | |
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| 74 | #include "fdlibm.h" |
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| 75 | #include <errno.h> |
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| 76 | |
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| 77 | #ifndef _DOUBLE_IS_32BITS |
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| 78 | |
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| 79 | #ifdef __STDC__ |
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| 80 | double asin(double x) /* wrapper asin */ |
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| 81 | #else |
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| 82 | double asin(x) /* wrapper asin */ |
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| 83 | double x; |
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| 84 | #endif |
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| 85 | { |
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| 86 | #ifdef _IEEE_LIBM |
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| 87 | return __ieee754_asin(x); |
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| 88 | #else |
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| 89 | double z; |
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| 90 | struct exception exc; |
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| 91 | z = __ieee754_asin(x); |
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| 92 | if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; |
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| 93 | if(fabs(x)>1.0) { |
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| 94 | /* asin(|x|>1) */ |
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| 95 | exc.type = DOMAIN; |
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| 96 | exc.name = "asin"; |
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| 97 | exc.err = 0; |
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| 98 | exc.arg1 = exc.arg2 = x; |
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| 99 | exc.retval = nan(""); |
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| 100 | if(_LIB_VERSION == _POSIX_) |
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| 101 | errno = EDOM; |
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| 102 | else if (!matherr(&exc)) { |
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| 103 | errno = EDOM; |
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| 104 | } |
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| 105 | if (exc.err != 0) |
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| 106 | errno = exc.err; |
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| 107 | return exc.retval; |
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| 108 | } else |
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| 109 | return z; |
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| 110 | #endif |
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| 111 | } |
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| 112 | |
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| 113 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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