floatundidf_ieee754.c revision 1.1 1 1.1 matt /* $NetBSD: floatundidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $ */
2 1.1 matt
3 1.1 matt /*-
4 1.1 matt * Copyright (c) 2013 The NetBSD Foundation, Inc.
5 1.1 matt * All rights reserved.
6 1.1 matt *
7 1.1 matt * This code is derived from software contributed to The NetBSD Foundation
8 1.1 matt * by Matt Thomas of 3am Software Foundry.
9 1.1 matt *
10 1.1 matt * Redistribution and use in source and binary forms, with or without
11 1.1 matt * modification, are permitted provided that the following conditions
12 1.1 matt * are met:
13 1.1 matt * 1. Redistributions of source code must retain the above copyright
14 1.1 matt * notice, this list of conditions and the following disclaimer.
15 1.1 matt * 2. Redistributions in binary form must reproduce the above copyright
16 1.1 matt * notice, this list of conditions and the following disclaimer in the
17 1.1 matt * documentation and/or other materials provided with the distribution.
18 1.1 matt *
19 1.1 matt * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 1.1 matt * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 1.1 matt * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 1.1 matt * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 1.1 matt * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 1.1 matt * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 1.1 matt * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 1.1 matt * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 1.1 matt * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 1.1 matt * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 1.1 matt * POSSIBILITY OF SUCH DAMAGE.
30 1.1 matt */
31 1.1 matt
32 1.1 matt #include <sys/cdefs.h>
33 1.1 matt #if defined(LIBC_SCCS) && !defined(lint)
34 1.1 matt __RCSID("$NetBSD: floatundidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $");
35 1.1 matt #endif /* LIBC_SCCS and not lint */
36 1.1 matt
37 1.1 matt #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
38 1.1 matt #include "softfloat/softfloat-for-gcc.h"
39 1.1 matt #endif
40 1.1 matt
41 1.1 matt #include <limits.h>
42 1.1 matt #include <machine/ieee.h>
43 1.1 matt #include "quad.h"
44 1.1 matt
45 1.1 matt /*
46 1.1 matt * Convert unsigned quad to double.
47 1.1 matt */
48 1.1 matt double
49 1.1 matt __floatundidf(u_quad_t x)
50 1.1 matt {
51 1.1 matt union ieee_double_u ux = { .dblu_d = 0.0 };
52 1.1 matt
53 1.1 matt if (x == 0)
54 1.1 matt return 0.0;
55 1.1 matt if (x == 1)
56 1.1 matt return 1.0;
57 1.1 matt
58 1.1 matt u_int l = __builtin_clzll(x);
59 1.1 matt x <<= (l + 1); /* clear implicit bit */
60 1.1 matt if (x == 0)
61 1.1 matt return 0x1.0p31;
62 1.1 matt x >>= 64 - (DBL_FRACHBITS + DBL_FRACLBITS);
63 1.1 matt union uu u = { .uq = x };
64 1.1 matt ux.dblu_frach = u.ul[H];
65 1.1 matt ux.dblu_fracl = u.ul[L];
66 1.1 matt ux.dblu_exp = DBL_EXP_BIAS + 63 - l;
67 1.1 matt
68 1.1 matt return ux.dblu_d;
69 1.1 matt }
70