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| 2 | /* @(#)w_sqrt.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 | <<sqrt>>, <<sqrtf>>---positive square root |
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| 17 | |
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| 18 | INDEX |
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| 19 | sqrt |
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| 20 | INDEX |
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| 21 | sqrtf |
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| 22 | |
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| 23 | SYNOPSIS |
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| 24 | #include <math.h> |
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| 25 | double sqrt(double <[x]>); |
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| 26 | float sqrtf(float <[x]>); |
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| 27 | |
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| 28 | DESCRIPTION |
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| 29 | <<sqrt>> computes the positive square root of the argument. |
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| 30 | You can modify error handling for this function with |
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| 31 | <<matherr>>. |
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| 32 | |
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| 33 | RETURNS |
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| 34 | On success, the square root is returned. If <[x]> is real and |
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| 35 | positive, then the result is positive. If <[x]> is real and |
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| 36 | negative, the global value <<errno>> is set to <<EDOM>> (domain error). |
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| 37 | |
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| 38 | |
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| 39 | PORTABILITY |
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| 40 | <<sqrt>> is ANSI C. <<sqrtf>> is an extension. |
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| 41 | */ |
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| 42 | |
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| 43 | /* |
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| 44 | * wrapper sqrt(x) |
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| 45 | */ |
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| 46 | |
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| 47 | #include "fdlibm.h" |
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| 48 | #include <errno.h> |
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| 49 | |
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| 50 | #ifndef _DOUBLE_IS_32BITS |
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| 51 | |
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| 52 | #ifdef __STDC__ |
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| 53 | double sqrt(double x) /* wrapper sqrt */ |
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| 54 | #else |
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| 55 | double sqrt(x) /* wrapper sqrt */ |
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| 56 | double x; |
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| 57 | #endif |
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| 58 | { |
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| 59 | #ifdef _IEEE_LIBM |
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| 60 | return __ieee754_sqrt(x); |
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| 61 | #else |
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| 62 | struct exception exc; |
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| 63 | double z; |
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| 64 | z = __ieee754_sqrt(x); |
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| 65 | if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; |
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| 66 | if(x<0.0) { |
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| 67 | exc.type = DOMAIN; |
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| 68 | exc.name = "sqrt"; |
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| 69 | exc.err = 0; |
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| 70 | exc.arg1 = exc.arg2 = x; |
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| 71 | if (_LIB_VERSION == _SVID_) |
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| 72 | exc.retval = 0.0; |
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| 73 | else |
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| 74 | exc.retval = 0.0/0.0; |
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| 75 | if (_LIB_VERSION == _POSIX_) |
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| 76 | errno = EDOM; |
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| 77 | else if (!matherr(&exc)) { |
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| 78 | errno = EDOM; |
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| 79 | } |
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| 80 | if (exc.err != 0) |
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| 81 | errno = exc.err; |
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| 82 | return exc.retval; |
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| 83 | } else |
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| 84 | return z; |
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| 85 | #endif |
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| 86 | } |
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| 87 | |
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| 88 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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