1 /* $NetBSD: fixunssfdi.c,v 1.9 2013/02/03 01:48:53 matt Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)fixunssfdi.c 8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: fixunssfdi.c,v 1.9 2013/02/03 01:48:53 matt Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44
45 #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
46 #include "softfloat/softfloat-for-gcc.h"
47 #endif
48
49 #include "quad.h"
50
51 #define ONE_FOURTH ((int)1 << (unsigned int)(INT_BITS - 2))
52 #define ONE_HALF (ONE_FOURTH * 2.0)
53 #define ONE (ONE_FOURTH * 4.0)
54
55 /*
56 * Convert float to (unsigned) quad. We do most of our work in double,
57 * out of sheer paranoia.
58 *
59 * Not sure what to do with negative numbers---for now, anything out
60 * of range becomes UQUAD_MAX.
61 *
62 * N.B.: must use new ANSI syntax (sorry).
63 */
64 u_quad_t
__fixunssfdi(float f)65 __fixunssfdi(float f)
66 {
67 double x, toppart;
68 union uu t;
69
70 if (f < 0)
71 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */
72 #ifdef notdef /* this falls afoul of a GCC bug */
73 if (f >= UQUAD_MAX)
74 return (UQUAD_MAX);
75 #else /* so we wire in 2^64-1 instead */
76 if (f >= 18446744073709551615.0) /* XXX */
77 return (UQUAD_MAX);
78 #endif
79 x = f;
80 /*
81 * Get the upper part of the result. Note that the divide
82 * may round up; we want to avoid this if possible, so we
83 * subtract `1/2' first.
84 */
85 toppart = (x - ONE_HALF) / ONE;
86 /*
87 * Now build a u_quad_t out of the top part. The difference
88 * between x and this is the bottom part (this may introduce
89 * a few fuzzy bits, but what the heck). With any luck this
90 * difference will be nonnegative: x should wind up in the
91 * range [0..UINT_MAX]. For paranoia, we assume [INT_MIN..
92 * 2*UINT_MAX] instead.
93 */
94 t.ul[H] = (unsigned int)toppart;
95 t.ul[L] = 0;
96 x -= (double)t.uq;
97 if (x < 0) {
98 t.ul[H]--;
99 x += UINT_MAX;
100 }
101 if (x > UINT_MAX) {
102 t.ul[H]++;
103 x -= UINT_MAX;
104 }
105 t.ul[L] = (u_int)x;
106 return (t.uq);
107 }
108