minix/lib/libm/src/s_floorl.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

112 lines
2.7 KiB
C

/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*
* From: @(#)s_floor.c 5.1 93/09/24
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: s_floorl.c,v 1.1 2013/11/11 23:57:34 joerg Exp $");
#if 0
__FBSDID("$FreeBSD: head/lib/msun/src/s_floorl.c 176280 2008-02-14 15:10:34Z bde $");
#endif
/*
* floorl(x)
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floorl(x).
*/
#include "namespace.h"
#include <float.h>
#include <math.h>
#include <stdint.h>
#include <machine/ieee.h>
#ifdef __HAVE_LONG_DOUBLE
#ifdef __weak_alias
__weak_alias(floorl, _floorl)
#endif
#ifdef LDBL_IMPLICIT_NBIT
#define MANH_SIZE (EXT_FRACHBITS + 1)
#define INC_MANH(ux, c) do { \
uint64_t oi = ux.extu_frach; \
ux.extu_frach += (c); \
if (ux.extu_frach < oi) \
ux.extu_exp++; \
} while (0)
#else
#define MANH_SIZE EXT_FRACHBITS
#define INC_MANH(ux, c) do { \
uint64_t oi = ux.extu_frach; \
ux.extu_frach += (c); \
if (ux.extu_frach < oi) { \
ux.extu_exp++; \
ux.extu_frach |= 1llu << (EXT_FRACHBITS - 1); \
} \
} while (0)
#endif
static const long double huge = 1.0e300;
long double
floorl(long double x)
{
union ieee_ext_u ux = { .extu_ld = x, };
int e = ux.extu_exp - LDBL_MAX_EXP + 1;
if (e < MANH_SIZE - 1) {
if (e < 0) { /* raise inexact if x != 0 */
if (huge + x > 0.0)
if (ux.extu_exp > 0 ||
(ux.extu_frach | ux.extu_fracl) != 0)
ux.extu_ld = ux.extu_sign ? -1.0 : 0.0;
} else {
uint64_t m = ((1llu << MANH_SIZE) - 1) >> (e + 1);
if (((ux.extu_frach & m) | ux.extu_fracl) == 0)
return (x); /* x is integral */
if (ux.extu_sign) {
#ifdef LDBL_IMPLICIT_NBIT
if (e == 0)
ux.extu_exp++;
else
#endif
INC_MANH(ux, 1llu << (MANH_SIZE - e - 1));
}
if (huge + x > 0.0) { /* raise inexact flag */
ux.extu_frach &= ~m;
ux.extu_fracl = 0;
}
}
} else if (e < LDBL_MANT_DIG - 1) {
uint64_t m = (uint64_t)-1 >> (64 - LDBL_MANT_DIG + e + 1);
if ((ux.extu_fracl & m) == 0)
return (x); /* x is integral */
if (ux.extu_sign) {
if (e == MANH_SIZE - 1)
INC_MANH(ux, 1);
else {
uint64_t o = ux.extu_fracl;
ux.extu_fracl += 1llu << (LDBL_MANT_DIG - e - 1);
if (ux.extu_fracl < o) /* got a carry */
INC_MANH(ux, 1);
}
}
if (huge + x > 0.0) /* raise inexact flag */
ux.extu_fracl &= ~m;
}
return (ux.extu_ld);
}
#endif /* __HAVE_LONG_DOUBLE */