57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
|
/* 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) = 0x80000001
|
||
|
|
* ilogbl(inf/NaN) = 0x7fffffff (no signal is raised)
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "math.h"
|
||
|
|
#include "math_private.h"
|
||
|
|
|
||
|
|
#ifdef __STDC__
|
||
|
|
int __ilogbl(long double x)
|
||
|
|
#else
|
||
|
|
int __ilogbl(x)
|
||
|
|
long double x;
|
||
|
|
#endif
|
||
|
|
{
|
||
|
|
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 0x80000001; /* ilogbl(0) = 0x80000001 */
|
||
|
|
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 return 0x7fffffff;
|
||
|
|
}
|
||
|
|
weak_alias (__ilogbl, ilogbl)
|