1 /* $NetBSD: fixdfdi_ieee754.c,v 1.1 2013/08/24 00:51:48 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 __RCSID("$NetBSD: fixdfdi_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $");
39 #endif /* LIBC_SCCS and not lint */
40
41 #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
42 #include "softfloat/softfloat-for-gcc.h"
43 #endif
44
45 #include "quad.h"
46 #include <limits.h>
47 #include <stdbool.h>
48 #include <machine/ieee.h>
49
50 /*
51 * Convert double to signed quad.
52 * Not sure what to do with negative numbers---for now, anything out
53 * of range becomes UQUAD_MAX.
54 */
55 quad_t
__fixdfdi(double x)56 __fixdfdi(double x)
57 {
58 const union ieee_double_u ux = { .dblu_d = x };
59 signed int exp = ux.dblu_exp - DBL_EXP_BIAS;
60 const bool neg = ux.dblu_sign;
61 quad_t r;
62
63 if (exp >= 62)
64 return neg ? QUAD_MIN : QUAD_MAX;
65
66 r = 1 << DBL_FRACHBITS; /* implicit bit */
67 r |= ux.dblu_frach;
68 exp -= DBL_FRACHBITS;
69 if (exp < 0) {
70 r >>= -exp;
71 } else if (exp > 0) {
72 r <<= DBL_FRACLBITS;
73 r |= ux.dblu_fracl;
74 exp -= DBL_FRACLBITS;
75 if (exp < 0) {
76 r >>= -exp;
77 } else if (exp > 0) {
78 r <<= exp;
79 }
80 }
81 return neg ? -r : r;
82 }
83