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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libm/] [common/] [s_isnan.c] - Rev 158
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/* @(#)s_isnan.c 5.1 93/09/24 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this * software is freely granted, provided that this notice * is preserved. * ==================================================== */ /* FUNCTION <<isnan>>, <<isnanf>>, <<isinf>>, <<isinff>>, <<finite>>, <<finitef>>---test for exceptional numbers INDEX isnan INDEX isinf INDEX finite INDEX isnanf INDEX isinff INDEX finitef ANSI_SYNOPSIS #include <ieeefp.h> int isnan(double <[arg]>); int isinf(double <[arg]>); int finite(double <[arg]>); int isnanf(float <[arg]>); int isinff(float <[arg]>); int finitef(float <[arg]>); TRAD_SYNOPSIS #include <ieeefp.h> int isnan(<[arg]>) double <[arg]>; int isinf(<[arg]>) double <[arg]>; int finite(<[arg]>); double <[arg]>; int isnanf(<[arg]>); float <[arg]>; int isinff(<[arg]>); float <[arg]>; int finitef(<[arg]>); float <[arg]>; DESCRIPTION These functions provide information on the floating-point argument supplied. There are five major number formats: o+ o zero A number which contains all zero bits. o subnormal A number with a zero exponent but a nonzero fraction. o normal A number with an exponent and a fraction. o infinity A number with an all 1's exponent and a zero fraction. o NAN A number with an all 1's exponent and a nonzero fraction. o- <<isnan>> returns 1 if the argument is a nan. <<isinf>> returns 1 if the argument is infinity. <<finite>> returns 1 if the argument is zero, subnormal or normal. The <<isnanf>>, <<isinff>> and <<finitef>> functions perform the same operations as their <<isnan>>, <<isinf>> and <<finite>> counterparts, but on single-precision floating-point numbers. It should be noted that the C99 standard dictates that <<isnan>> and <<isinf>> are macros that operate on multiple types of floating-point. The SUSv2 standard declares <<isnan>> as a function taking double. Newlib has decided to declare them both as macros in math.h and as functions in ieeefp.h. QUICKREF isnan - pure QUICKREF isinf - pure QUICKREF finite - pure QUICKREF isnan - pure QUICKREF isinf - pure QUICKREF finite - pure */ /* * isnan(x) returns 1 is x is nan, else 0; * no branching! * * The C99 standard dictates that isnan is a macro taking * multiple floating-point types while the SUSv2 standard * notes it is a function taking a double argument. Newlib * has chosen to implement it as a macro in <math.h> and * declare it as a function in <ieeefp.h>. */ #include "fdlibm.h" #include <ieeefp.h> #ifndef _DOUBLE_IS_32BITS #ifdef __STDC__ int isnan(double x) #else int isnan(x) double x; #endif { __int32_t hx,lx; EXTRACT_WORDS(hx,lx,x); hx &= 0x7fffffff; hx |= (__uint32_t)(lx|(-lx))>>31; hx = 0x7ff00000 - hx; return (int)(((__uint32_t)(hx))>>31); } #endif /* _DOUBLE_IS_32BITS */
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