Annotation of src/lib/libc/quad/floatundidf_ieee754.c, Revision 1.2
1.2 ! mlelstv 1: /* $NetBSD: floatundidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $ */
1.1 matt 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)
1.2 ! mlelstv 34: __RCSID("$NetBSD: floatundidf_ieee754.c,v 1.1 2013/08/24 00:51:48 matt Exp $");
1.1 matt 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 <limits.h>
42: #include <machine/ieee.h>
43: #include "quad.h"
44:
45: /*
46: * Convert unsigned quad to double.
47: */
48: double
49: __floatundidf(u_quad_t x)
50: {
51: union ieee_double_u ux = { .dblu_d = 0.0 };
52:
53: if (x == 0)
54: return 0.0;
55:
56: u_int l = __builtin_clzll(x);
57: x <<= (l + 1); /* clear implicit bit */
58: x >>= 64 - (DBL_FRACHBITS + DBL_FRACLBITS);
59: union uu u = { .uq = x };
60: ux.dblu_frach = u.ul[H];
61: ux.dblu_fracl = u.ul[L];
62: ux.dblu_exp = DBL_EXP_BIAS + 63 - l;
63:
64: return ux.dblu_d;
65: }
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