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43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
/* s_logbl.c -- long double version of s_logb.c.
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* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
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*/
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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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#if defined(LIBM_SCCS) && !defined(lint)
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static char rcsid[] = "$NetBSD: $";
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#endif
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/*
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* long double logbl(x)
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* IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
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* Use ilogb instead.
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*/
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#include "math.h"
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#include "math_private.h"
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#include <math_ldbl_opt.h>
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long double __logbl(long double x)
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{
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int64_t lx,hx;
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GET_LDOUBLE_WORDS64(hx,lx,x);
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hx &= 0x7fffffffffffffffLL; /* high |x| */
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if((hx|(lx&0x7fffffffffffffffLL))==0) return -1.0/fabs(x);
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if(hx>=0x7ff0000000000000LL) return x*x;
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if((hx>>=52)==0) /* IEEE 754 logb */
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return -1022.0;
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else
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return (long double) (hx-0x3ff);
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}
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long_double_symbol (libm, __logbl, logbl);
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