diff options
author | David Schultz <das@FreeBSD.org> | 2005-01-22 06:03:40 +0000 |
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committer | David Schultz <das@FreeBSD.org> | 2005-01-22 06:03:40 +0000 |
commit | 00646ca2047305fce32d99edc7a8e6dfd801f3b4 (patch) | |
tree | 453d24603f8076b2c01c839cddf81fa32e3c6416 /lib/libc/powerpc/gen | |
parent | 4d28b4d2061de712c2f21e3f71d562ce698f8ab8 (diff) | |
download | src-00646ca2047305fce32d99edc7a8e6dfd801f3b4.tar.gz src-00646ca2047305fce32d99edc7a8e6dfd801f3b4.zip |
Replace the ldexp() implementation in libc with a renamed copy of the
scalbn() implementation from libm. (The two functions are defined to
be identical, but ldexp() lives in libc for backwards compatibility.)
The old ldexp() implementation...
- was more complicated than this one
- set errno instead of raising FP exceptions
- got some corner cases wrong
(e.g. ldexp(1.0, 2000) in round-to-zero mode)
The new implementation lives in libc/gen instead of
libc/$MACHINE_ARCH/gen, since we don't need N copies of a
machine-independent file. The amd64 and i386 platforms
retain their fast and correct MD implementations and
override this one.
Notes
Notes:
svn path=/head/; revision=140607
Diffstat (limited to 'lib/libc/powerpc/gen')
-rw-r--r-- | lib/libc/powerpc/gen/ldexp.c | 155 |
1 files changed, 0 insertions, 155 deletions
diff --git a/lib/libc/powerpc/gen/ldexp.c b/lib/libc/powerpc/gen/ldexp.c deleted file mode 100644 index 3a85612d47dd..000000000000 --- a/lib/libc/powerpc/gen/ldexp.c +++ /dev/null @@ -1,155 +0,0 @@ -/*- - * Copyright (c) 1999 The NetBSD Foundation, Inc. - * All rights reserved. - * - * This code is derived from software contributed to The NetBSD Foundation - * by Charles M. Hannum. - * - * 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. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the NetBSD - * Foundation, Inc. and its contributors. - * 4. Neither the name of The NetBSD Foundation nor the names of its - * contributors may be used to endorse or promote products derived - * from this software without specific prior written permission. - * - * 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 <sys/cdefs.h> -#if 0 -#if defined(LIBC_SCCS) && !defined(lint) -__RCSID("$NetBSD: ldexp.c,v 1.8 1999/08/30 18:28:26 mycroft Exp $"); -#endif /* LIBC_SCCS and not lint */ -#endif -__FBSDID("$FreeBSD$"); - -#include <sys/types.h> -#include <machine/ieee.h> -#include <errno.h> -#include <math.h> - -/* - * Multiply the given value by 2^exp. - */ -double -ldexp(val, exp) - double val; - int exp; -{ - int oldexp, newexp; - union { - double v; - struct ieee_double s; - } u, mul; - - u.v = val; - oldexp = u.s.dbl_exp; - - /* - * If input is zero, Inf or NaN, just return it. - */ - if (u.v == 0.0 || oldexp == DBL_EXP_INFNAN) - return (val); - - if (oldexp == 0) { - /* - * u.v is denormal. We must adjust it so that the exponent - * arithmetic below will work. - */ - if (exp <= DBL_EXP_BIAS) { - /* - * Optimization: if the scaling can be done in a single - * multiply, or underflows, just do it now. - */ - if (exp <= -DBL_FRACBITS) { - errno = ERANGE; - return (0.0); - } - mul.v = 0.0; - mul.s.dbl_exp = exp + DBL_EXP_BIAS; - u.v *= mul.v; - if (u.v == 0.0) { - errno = ERANGE; - return (0.0); - } - return (u.v); - } else { - /* - * We know that exp is very large, and therefore the - * result cannot be denormal (though it may be Inf). - * Shift u.v by just enough to make it normal. - */ - mul.v = 0.0; - mul.s.dbl_exp = DBL_FRACBITS + DBL_EXP_BIAS; - u.v *= mul.v; - exp -= DBL_FRACBITS; - oldexp = u.s.dbl_exp; - } - } - - /* - * u.v is now normalized and oldexp has been adjusted if necessary. - * Calculate the new exponent and check for underflow and overflow. - */ - newexp = oldexp + exp; - - if (newexp <= 0) { - /* - * The output number is either denormal or underflows (see - * comments in machine/ieee.h). - */ - if (newexp <= -DBL_FRACBITS) { - errno = ERANGE; - return (0.0); - } - /* - * Denormalize the result. We do this with a multiply. If exp - * is very large, it won't fit in a double, so we have to - * adjust the exponent first. This is safe because we know - * that u.v is normal at this point. - */ - if (exp <= -DBL_EXP_BIAS) { - u.s.dbl_exp = 1; - exp += oldexp - 1; - } - mul.v = 0.0; - mul.s.dbl_exp = exp + DBL_EXP_BIAS; - u.v *= mul.v; - return (u.v); - } else if (newexp >= DBL_EXP_INFNAN) { - /* - * The result overflowed; return +/-Inf. - */ - u.s.dbl_exp = DBL_EXP_INFNAN; - u.s.dbl_frach = 0; - u.s.dbl_fracl = 0; - errno = ERANGE; - return (u.v); - } else { - /* - * The result is normal; just replace the old exponent with the - * new one. - */ - u.s.dbl_exp = newexp; - return (u.v); - } -} |