| 1 | /* |
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| 2 | * ==================================================== |
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| 3 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 4 | * |
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| 5 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 6 | * Permission to use, copy, modify, and distribute this |
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| 7 | * software is freely granted, provided that this notice |
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| 8 | * is preserved. |
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| 9 | * ==================================================== |
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| 10 | */ |
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| 11 | |
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| 12 | /* |
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| 13 | FUNCTION |
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| 14 | <<isnan>>, <<isnanf>>, <<isinf>>, <<isinff>>, <<finite>>, <<finitef>>---test for exceptional numbers |
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| 15 | |
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| 16 | INDEX |
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| 17 | isnan |
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| 18 | INDEX |
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| 19 | isinf |
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| 20 | INDEX |
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| 21 | finite |
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| 22 | |
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| 23 | INDEX |
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| 24 | isnanf |
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| 25 | INDEX |
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| 26 | isinff |
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| 27 | INDEX |
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| 28 | finitef |
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| 29 | |
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| 30 | SYNOPSIS |
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| 31 | #include <math.h> |
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| 32 | int isnan(double <[arg]>); |
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| 33 | int isinf(double <[arg]>); |
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| 34 | int finite(double <[arg]>); |
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| 35 | int isnanf(float <[arg]>); |
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| 36 | int isinff(float <[arg]>); |
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| 37 | int finitef(float <[arg]>); |
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| 38 | |
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| 39 | |
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| 40 | DESCRIPTION |
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| 41 | These functions provide information on the floating-point |
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| 42 | argument supplied. |
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| 43 | |
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| 44 | There are five major number formats: |
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| 45 | o+ |
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| 46 | o zero |
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| 47 | A number which contains all zero bits. |
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| 48 | o subnormal |
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| 49 | A number with a zero exponent but a nonzero fraction. |
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| 50 | o normal |
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| 51 | A number with an exponent and a fraction. |
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| 52 | o infinity |
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| 53 | A number with an all 1's exponent and a zero fraction. |
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| 54 | o NAN |
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| 55 | A number with an all 1's exponent and a nonzero fraction. |
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| 56 | |
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| 57 | o- |
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| 58 | |
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| 59 | <<isnan>> returns 1 if the argument is a nan. <<isinf>> |
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| 60 | returns 1 if the argument is infinity. <<finite>> returns 1 if the |
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| 61 | argument is zero, subnormal or normal. |
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| 62 | |
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| 63 | Note that by the C99 standard, <<isnan>> and <<isinf>> are macros |
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| 64 | taking any type of floating-point and are declared in |
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| 65 | <<math.h>>. Newlib has chosen to declare these both as functions |
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| 66 | and as macros in <<math.h>>. |
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| 67 | |
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| 68 | The <<isnanf>>, <<isinff>> and <<finitef>> functions perform the same |
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| 69 | operations as their <<isnan>>, <<isinf>> and <<finite>> |
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| 70 | counterparts, but on single-precision floating-point numbers. |
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| 71 | |
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| 72 | QUICKREF |
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| 73 | isnan - pure |
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| 74 | QUICKREF |
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| 75 | isinf - pure |
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| 76 | QUICKREF |
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| 77 | finite - pure |
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| 78 | QUICKREF |
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| 79 | isnan - pure |
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| 80 | QUICKREF |
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| 81 | isinf - pure |
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| 82 | QUICKREF |
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| 83 | finite - pure |
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| 84 | */ |
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| 85 | |
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| 86 | /* |
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| 87 | * __isnand(x) returns 1 is x is nan, else 0; |
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| 88 | * no branching! |
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| 89 | */ |
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| 90 | |
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| 91 | #include "fdlibm.h" |
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| 92 | |
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| 93 | #ifndef _DOUBLE_IS_32BITS |
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| 94 | |
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| 95 | int |
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| 96 | __isnand (double x) |
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| 97 | { |
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| 98 | __int32_t hx,lx; |
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| 99 | EXTRACT_WORDS(hx,lx,x); |
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| 100 | hx &= 0x7fffffff; |
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| 101 | hx |= (__uint32_t)(lx|(-lx))>>31; |
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| 102 | hx = 0x7ff00000 - hx; |
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| 103 | return (int)(((__uint32_t)(hx))>>31); |
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| 104 | } |
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| 105 | |
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| 106 | #endif /* _DOUBLE_IS_32BITS */ |
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