diff options
Diffstat (limited to 'lib/libc/gen/frexp.c')
-rw-r--r-- | lib/libc/gen/frexp.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/lib/libc/gen/frexp.c b/lib/libc/gen/frexp.c new file mode 100644 index 00000000000..97cc624035a --- /dev/null +++ b/lib/libc/gen/frexp.c @@ -0,0 +1,79 @@ +/* $OpenBSD: frexp.c,v 1.7 2011/07/08 22:28:33 martynas Exp $ */ + +/*- + * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG> + * 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 <sys/types.h> +#include <sys/cdefs.h> +#include <machine/ieee.h> +#include <float.h> +#include <math.h> + +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 */ |