| /* 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" |
| |
| #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 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; |
| } |
| weak_alias (__ilogbl, ilogbl) |
