/* $OpenBSD: frexp.c,v 1.7 2011/07/08 22:28:33 martynas Exp $ */ /*- * Copyright (c) 2004 David Schultz * All rights reserved. * * 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 AUTHOR 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 AUTHOR 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. * * $FreeBSD: frexp.c,v 1.1 2004/07/18 21:23:39 das Exp $ */ /* LINTLIBRARY */ #include #include #include #include #include double frexp(double v, int *ex) { union { double v; struct ieee_double s; } u; u.v = v; switch (u.s.dbl_exp) { case 0: /* 0 or subnormal */ if ((u.s.dbl_fracl | u.s.dbl_frach) == 0) { *ex = 0; } else { /* * The power of 2 is arbitrary, any value from 54 to * 1024 will do. */ u.v *= 0x1.0p514; *ex = u.s.dbl_exp - (DBL_EXP_BIAS - 1 + 514); u.s.dbl_exp = DBL_EXP_BIAS - 1; } break; case DBL_EXP_INFNAN: /* Inf or NaN; value of *ex is unspecified */ break; default: /* normal */ *ex = u.s.dbl_exp - (DBL_EXP_BIAS - 1); u.s.dbl_exp = DBL_EXP_BIAS - 1; break; } return (u.v); } #if LDBL_MANT_DIG == 53 #ifdef lint /* PROTOLIB1 */ long double frexpl(long double, int *); #else /* lint */ __weak_alias(frexpl, frexp); #endif /* lint */ #endif /* LDBL_MANT_DIG == 53 */