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60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
/* Copyright (C) 2002 by Red Hat, Incorporated. All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software
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* is freely granted, provided that this notice is preserved.
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*/
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/*
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FUNCTION
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<<signbit>>--Does floating-point number have negative sign?
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INDEX
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signbit
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ANSI_SYNOPSIS
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#include <math.h>
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int signbit(real-floating <[x]>);
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DESCRIPTION
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The <<signbit>> macro determines whether the sign of its argument value is
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negative. The macro reports the sign of all values, including infinities,
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zeros, and NaNs. If zero is unsigned, it is treated as positive. As shown in
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the synopsis, the argument is "real-floating," meaning that any of the real
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floating-point types (float, double, etc.) may be given to it.
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Note that because of the possibilities of signed 0 and NaNs, the expression
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"<[x]> < 0.0" does not give the same result as <<signbit>> in all cases.
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RETURNS
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The <<signbit>> macro returns a nonzero value if and only if the sign of its
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argument value is negative.
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PORTABILITY
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C99, POSIX.
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*/
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#include "fdlibm.h"
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int __signbitf (float x);
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int __signbitd (double x);
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int
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__signbitf (float x)
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{
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unsigned int w;
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GET_FLOAT_WORD(w,x);
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return (w & 0x80000000);
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}
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int
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__signbitd (double x)
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{
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unsigned int msw;
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GET_HIGH_WORD(msw, x);
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return (msw & 0x80000000);
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}
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