/* $NetBSD: s_ilogbl.c,v 1.4 2016/08/26 08:20:31 christos Exp $ */ /*- * Copyright (c) 2011 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Joerg Sonnenberger. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include __RCSID("$NetBSD: s_ilogbl.c,v 1.4 2016/08/26 08:20:31 christos Exp $"); #include "namespace.h" #include #include #define __TEST_FENV #include #ifndef __HAVE_FENV #define feraiseexcept(a) #endif #include #ifdef __HAVE_LONG_DOUBLE #if LDBL_MANT_DIG == 64 #define FROM_UNDERFLOW 0x1p65L #elif LDBL_MANT_DIG == 113 #define FROM_UNDERFLOW 0x1p114L #else #error Unsupported long double format #endif int ilogbl(long double x) { union ieee_ext_u u; if (x == 0.0L) { feraiseexcept(FE_INVALID); return FP_ILOGB0; /* ilogbl(0) = 0x80000001 */ } u.extu_ld = x; if (u.extu_ext.ext_exp == EXT_EXP_INFNAN) { feraiseexcept(FE_INVALID); return isnan(x) ? FP_ILOGBNAN : INT_MAX; } if (u.extu_ext.ext_exp == 0) { /* * Scale denormalized numbers slightly, * so that they are normal. */ u.extu_ld *= FROM_UNDERFLOW; return u.extu_ext.ext_exp - EXT_EXP_BIAS - LDBL_MANT_DIG - 1; } return u.extu_ext.ext_exp - EXT_EXP_BIAS; } #endif