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/* s_ilogbl.c -- long double version of s_ilogb.c.
* Conversion to long double by Ulrich Drepper,
* Cygnus Support, drepper@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif
/* ilogbl(long double x)
* return the binary exponent of non-zero x
* ilogbl(0) = FP_ILOGB0
* ilogbl(NaN) = FP_ILOGBNAN (no signal is raised)
* ilogbl(+-Inf) = INT_MAX (no signal is raised)
*/
#include <limits.h>
#include <math.h>
#include <math_private.h>
int __ieee754_ilogbl (long double x)
{
int32_t es,hx,lx,ix;
GET_LDOUBLE_EXP(es,x);
es &= 0x7fff;
if(es==0) {
GET_LDOUBLE_WORDS(es,hx,lx,x);
if((hx|lx)==0)
return FP_ILOGB0; /* ilogbl(0) = FP_ILOGB0 */
else /* subnormal x */
if(hx==0) {
for (ix = -16415; lx>0; lx<<=1) ix -=1;
} else {
for (ix = -16383; hx>0; hx<<=1) ix -=1;
}
return ix;
}
else if (es<0x7fff) return es-0x3fff;
else if (FP_ILOGBNAN != INT_MAX)
{
GET_LDOUBLE_WORDS(es,hx,lx,x);
if (((hx & 0x7fffffff)|lx) == 0)
/* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
return INT_MAX;
}
return FP_ILOGBNAN;
}
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