minix/lib/libm/src/s_nan.c
Lionel Sambuc 84d9c625bf Synchronize on NetBSD-CVS (2013/12/1 12:00:00 UTC)
- Fix for possible unset uid/gid in toproto
 - Fix for default mtree style
 - Update libelf
 - Importing libexecinfo
 - Resynchronize GCC, mpc, gmp, mpfr
 - build.sh: Replace params with show-params.
     This has been done as the make target has been renamed in the same
     way, while a new target named params has been added. This new
     target generates a file containing all the parameters, instead of
     printing it on the console.
 - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
     get getservbyport() out of the inner loop

Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
2014-07-28 17:05:06 +02:00

125 lines
3.7 KiB
C

/* $NetBSD: s_nan.c,v 1.2 2013/02/09 20:19:13 christos Exp $ */
/*-
* Copyright (c) 2007 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 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 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: src/lib/msun/src/s_nan.c,v 1.2 2007/12/18 23:46:32 das Exp $
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: s_nan.c,v 1.2 2013/02/09 20:19:13 christos Exp $");
#include <sys/endian.h>
#include <ctype.h>
#include <float.h>
#include <math.h>
#include <stdint.h>
#include <string.h>
#include "math_private.h"
/* XXX: Locale? not here? in <ctype.h>? */
static int
digittoint(char s) {
if (isdigit((unsigned char)s))
return s - '0';
if (islower((unsigned char)s))
return s - 'a' + 10;
return s - 'A' + 10;
}
/*
* Scan a string of hexadecimal digits (the format nan(3) expects) and
* make a bit array (using the local endianness). We stop when we
* encounter an invalid character, NUL, etc. If we overflow, we do
* the same as gcc's __builtin_nan(), namely, discard the high order bits.
*
* The format this routine accepts needs to be compatible with what is used
* in contrib/gdtoa/hexnan.c (for strtod/scanf) and what is used in
* __builtin_nan(). In fact, we're only 100% compatible for strings we
* consider valid, so we might be violating the C standard. But it's
* impossible to use nan(3) portably anyway, so this seems good enough.
*/
static void
_scan_nan(uint32_t *words, int num_words, const char *s)
{
int si; /* index into s */
int bitpos; /* index into words (in bits) */
memset(words, 0, num_words * sizeof(*words));
/* Allow a leading '0x'. (It's expected, but redundant.) */
if (s[0] == '0' && (s[1] == 'x' || s[1] == 'X'))
s += 2;
/* Scan forwards in the string, looking for the end of the sequence. */
for (si = 0; isxdigit((unsigned char)s[si]); si++)
continue;
/* Scan backwards, filling in the bits in words[] as we go. */
#if _BYTE_ORDER == _LITTLE_ENDIAN
for (bitpos = 0; bitpos < 32 * num_words; bitpos += 4) {
#else
for (bitpos = 32 * num_words - 4; bitpos >= 0; bitpos -= 4) {
#endif
if (--si < 0)
break;
words[bitpos / 32] |= digittoint(s[si]) << (bitpos % 32);
}
}
double
nan(const char *s)
{
union {
double d;
uint32_t bits[2];
} u;
_scan_nan(u.bits, 2, s);
#if _BYTE_ORDER == _LITTLE_ENDIAN
u.bits[1] |= 0x7ff80000;
#else
u.bits[0] |= 0x7ff80000;
#endif
return (u.d);
}
float
nanf(const char *s)
{
union {
float f;
uint32_t bits[1];
} u;
_scan_nan(u.bits, 1, s);
u.bits[0] |= 0x7fc00000;
return (u.f);
}
#if (LDBL_MANT_DIG == 53)
__weak_reference(nan, nanl);
#endif