1 /* $NetBSD: floatunsidf_ieee754.c,v 1.1 2013/08/23 16:01:35 matt Exp $ */
2
3 /*-
4 * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matt Thomas of 3am Software Foundry.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: floatunsidf_ieee754.c,v 1.1 2013/08/23 16:01:35 matt Exp $");
35 #endif /* LIBC_SCCS and not lint */
36
37 #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
38 #include "softfloat/softfloat-for-gcc.h"
39 #endif
40
41 #include <machine/ieee.h>
42
43 double __floatunsidf(uint32_t);
44
45 /*
46 * Convert (unsigned) int to double.
47 */
48 double
__floatunsidf(uint32_t x)49 __floatunsidf(uint32_t x)
50 {
51 union ieee_double_u u;
52
53 if (x == 0)
54 return 0.0;
55 if (x == 1)
56 return 1.0;
57
58 u_int l = __builtin_clz(x);
59 x <<= (l + 1); /* clear implicit bit */
60
61 u.dblu_sign = 0;
62 u.dblu_exp = DBL_EXP_BIAS + 31 - l;
63 u.dblu_frach = x >> (32 - DBL_FRACHBITS);
64 u.dblu_fracl = x << (32 - DBL_FRACHBITS);
65
66 return u.dblu_d;
67 }
68