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66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
/* s_ilogbl.c -- long double version of s_ilogb.c.
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* Conversion to long double by Ulrich Drepper,
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* Cygnus Support, drepper@cygnus.com.
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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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/* ilogbl(long double x)
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* return the binary exponent of non-zero x
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* ilogbl(0) = FP_ILOGB0
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* ilogbl(NaN) = FP_ILOGBNAN (no signal is raised)
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* ilogbl(+-Inf) = INT_MAX (no signal is raised)
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*/
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#include <limits.h>
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#include "math.h"
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#include "math_private.h"
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#ifdef __STDC__
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int __ilogbl(long double x)
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#else
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int __ilogbl(x)
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long double x;
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#endif
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{
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int32_t es,hx,lx,ix;
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GET_LDOUBLE_EXP(es,x);
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es &= 0x7fff;
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if(es==0) {
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GET_LDOUBLE_WORDS(es,hx,lx,x);
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if((hx|lx)==0)
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return FP_ILOGB0; /* ilogbl(0) = FP_ILOGB0 */
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else /* subnormal x */
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if(hx==0) {
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for (ix = -16415; lx>0; lx<<=1) ix -=1;
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} else {
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for (ix = -16383; hx>0; hx<<=1) ix -=1;
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}
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return ix;
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}
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else if (es<0x7fff) return es-0x3fff;
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else if (FP_ILOGBNAN != INT_MAX)
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{
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GET_LDOUBLE_WORDS(es,hx,lx,x);
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if ((hx & 0x7fffffff|lx) == 0)
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/* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
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return INT_MAX;
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}
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return FP_ILOGBNAN;
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}
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weak_alias (__ilogbl, ilogbl)
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