mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-29 12:03:03 +00:00
101 lines
3.5 KiB
C
101 lines
3.5 KiB
C
/*-
|
|
* Copyright (c) 1992, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This software was developed by the Computer Systems Engineering group
|
|
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
|
|
* contributed to Berkeley.
|
|
*
|
|
* 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 University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
|
|
*/
|
|
|
|
#if defined(LIBC_SCCS) && !defined(lint)
|
|
static char sccsid[] = "@(#)fixunssfdi.c 8.1 (Berkeley) 6/4/93";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
|
|
#include "quad.h"
|
|
|
|
#define ONE_FOURTH (1 << (LONG_BITS - 2))
|
|
#define ONE_HALF (ONE_FOURTH * 2.0)
|
|
#define ONE (ONE_FOURTH * 4.0)
|
|
|
|
/*
|
|
* Convert float to (unsigned) quad. We do most of our work in double,
|
|
* out of sheer paranoia.
|
|
*
|
|
* Not sure what to do with negative numbers---for now, anything out
|
|
* of range becomes UQUAD_MAX.
|
|
*
|
|
* N.B.: must use new ANSI syntax (sorry).
|
|
*/
|
|
u_quad_t
|
|
__fixunssfdi(float f)
|
|
{
|
|
double x, toppart;
|
|
union uu t;
|
|
|
|
if (f < 0)
|
|
return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */
|
|
#ifdef notdef /* this falls afoul of a GCC bug */
|
|
if (f >= UQUAD_MAX)
|
|
return (UQUAD_MAX);
|
|
#else /* so we wire in 2^64-1 instead */
|
|
if (f >= 18446744073709551615.0)
|
|
return (UQUAD_MAX);
|
|
#endif
|
|
x = f;
|
|
/*
|
|
* Get the upper part of the result. Note that the divide
|
|
* may round up; we want to avoid this if possible, so we
|
|
* subtract `1/2' first.
|
|
*/
|
|
toppart = (x - ONE_HALF) / ONE;
|
|
/*
|
|
* Now build a u_quad_t out of the top part. The difference
|
|
* between x and this is the bottom part (this may introduce
|
|
* a few fuzzy bits, but what the heck). With any luck this
|
|
* difference will be nonnegative: x should wind up in the
|
|
* range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN..
|
|
* 2*ULONG_MAX] instead.
|
|
*/
|
|
t.ul[H] = (unsigned long)toppart;
|
|
t.ul[L] = 0;
|
|
x -= (double)t.uq;
|
|
if (x < 0) {
|
|
t.ul[H]--;
|
|
x += ULONG_MAX;
|
|
}
|
|
if (x > ULONG_MAX) {
|
|
t.ul[H]++;
|
|
x -= ULONG_MAX;
|
|
}
|
|
t.ul[L] = (u_long)x;
|
|
return (t.uq);
|
|
}
|