1/*	$OpenBSD: floatdisf.c,v 1.8 2019/11/10 22:23:28 guenther Exp $ */
2/*-
3 * Copyright (c) 1992, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * This software was developed by the Computer Systems Engineering group
7 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
8 * contributed to Berkeley.
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 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include "quad.h"
36
37/*
38 * Convert (signed) quad to float.
39 */
40float
41__floatdisf(quad_t x)
42{
43	float f;
44	union uu u;
45	int neg;
46
47	/*
48	 * Get an unsigned number first, by negating if necessary.
49	 */
50	if (x < 0)
51		u.q = -x, neg = 1;
52	else
53		u.q = x, neg = 0;
54
55	/*
56	 * Now u.ul[H] has the factor of 2^32 (or whatever) and u.ul[L]
57	 * has the units.  Ideally we could just set f, add INT_BITS to
58	 * its exponent, and then add the units, but this is portable
59	 * code and does not know how to get at an exponent.  Machine-
60	 * specific code may be able to do this more efficiently.
61	 *
62	 * Using double here may be excessive paranoia.
63	 */
64	f = (double)u.ul[H] * (((int)1 << (INT_BITS - 2)) * 4.0);
65	f += u.ul[L];
66
67	return (neg ? -f : f);
68}
69
70#ifdef __ARM_EABI__
71__strong_alias(__aeabi_l2f, __floatdisf);
72__asm(".protected __aeabi_l2f");
73#endif
74