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/* @(#)s_frexp.c 1.4 95/01/18 */
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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 SunSoft, 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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* for non-zero x
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* x = ieee_frexp(arg,&exp);
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* return a double fp quantity x such that 0.5 <= |x| <1.0
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* and the corresponding binary exponent "exp". That is
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* arg = x*2^exp.
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* If arg is inf, 0.0, or NaN, then ieee_frexp(arg,&exp) returns arg
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* with *exp=0.
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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static const double
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#else
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static double
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#endif
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two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */
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#ifdef __STDC__
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double ieee_frexp(double x, int *eptr)
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#else
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double ieee_frexp(x, eptr)
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double x; int *eptr;
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#endif
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{
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int hx, ix, lx;
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hx = __HI(x);
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ix = 0x7fffffff&hx;
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lx = __LO(x);
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*eptr = 0;
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if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */
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if (ix<0x00100000) { /* subnormal */
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x *= two54;
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hx = __HI(x);
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ix = hx&0x7fffffff;
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*eptr = -54;
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}
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*eptr += (ix>>20)-1022;
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hx = (hx&0x800fffff)|0x3fe00000;
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__HI(x) = hx;
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return x;
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}
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