82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
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/* @(#)s_ldexp.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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FUNCTION
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<<ldexp>>, <<ldexpf>>---load exponent
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INDEX
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ldexp
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INDEX
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ldexpf
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ANSI_SYNOPSIS
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#include <math.h>
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double ldexp(double <[val]>, int <[exp]>);
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float ldexpf(float <[val]>, int <[exp]>);
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TRAD_SYNOPSIS
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#include <math.h>
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double ldexp(<[val]>, <[exp]>)
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double <[val]>;
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int <[exp]>;
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float ldexpf(<[val]>, <[exp]>)
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float <[val]>;
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int <[exp]>;
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DESCRIPTION
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<<ldexp>> calculates the value
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@ifinfo
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<[val]> times 2 to the power <[exp]>.
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@end ifinfo
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@tex
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$val\times 2^{exp}$.
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@end tex
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<<ldexpf>> is identical, save that it takes and returns <<float>>
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rather than <<double>> values.
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RETURNS
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<<ldexp>> returns the calculated value.
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Underflow and overflow both set <<errno>> to <<ERANGE>>.
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On underflow, <<ldexp>> and <<ldexpf>> return 0.0.
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On overflow, <<ldexp>> returns plus or minus <<HUGE_VAL>>.
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PORTABILITY
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<<ldexp>> is ANSI, <<ldexpf>> is an extension.
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*/
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#include "fdlibm.h"
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#include <errno.h>
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#ifndef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double ldexp(double value, int exp)
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#else
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double ldexp(value, exp)
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double value; int exp;
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#endif
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{
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if(!finite(value)||value==0.0) return value;
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value = scalbn(value,exp);
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if(!finite(value)||value==0.0) errno = ERANGE;
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return value;
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}
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#endif /* _DOUBLE_IS_32BITS */
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