xref: /minix3/lib/libc/gen/floatunsidf_ieee754.c (revision 84d9c625bfea59e274550651111ae9edfdc40fbd)
1*84d9c625SLionel Sambuc /*	$NetBSD: floatunsidf_ieee754.c,v 1.1 2013/08/23 16:01:35 matt Exp $	*/
2*84d9c625SLionel Sambuc 
3*84d9c625SLionel Sambuc /*-
4*84d9c625SLionel Sambuc  * Copyright (c) 2013 The NetBSD Foundation, Inc.
5*84d9c625SLionel Sambuc  * All rights reserved.
6*84d9c625SLionel Sambuc  *
7*84d9c625SLionel Sambuc  * This code is derived from software contributed to The NetBSD Foundation
8*84d9c625SLionel Sambuc  * by Matt Thomas of 3am Software Foundry.
9*84d9c625SLionel Sambuc  *
10*84d9c625SLionel Sambuc  * Redistribution and use in source and binary forms, with or without
11*84d9c625SLionel Sambuc  * modification, are permitted provided that the following conditions
12*84d9c625SLionel Sambuc  * are met:
13*84d9c625SLionel Sambuc  * 1. Redistributions of source code must retain the above copyright
14*84d9c625SLionel Sambuc  *    notice, this list of conditions and the following disclaimer.
15*84d9c625SLionel Sambuc  * 2. Redistributions in binary form must reproduce the above copyright
16*84d9c625SLionel Sambuc  *    notice, this list of conditions and the following disclaimer in the
17*84d9c625SLionel Sambuc  *    documentation and/or other materials provided with the distribution.
18*84d9c625SLionel Sambuc  *
19*84d9c625SLionel Sambuc  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*84d9c625SLionel Sambuc  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*84d9c625SLionel Sambuc  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*84d9c625SLionel Sambuc  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*84d9c625SLionel Sambuc  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*84d9c625SLionel Sambuc  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*84d9c625SLionel Sambuc  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*84d9c625SLionel Sambuc  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*84d9c625SLionel Sambuc  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*84d9c625SLionel Sambuc  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*84d9c625SLionel Sambuc  * POSSIBILITY OF SUCH DAMAGE.
30*84d9c625SLionel Sambuc  */
31*84d9c625SLionel Sambuc 
32*84d9c625SLionel Sambuc #include <sys/cdefs.h>
33*84d9c625SLionel Sambuc #if defined(LIBC_SCCS) && !defined(lint)
34*84d9c625SLionel Sambuc __RCSID("$NetBSD: floatunsidf_ieee754.c,v 1.1 2013/08/23 16:01:35 matt Exp $");
35*84d9c625SLionel Sambuc #endif /* LIBC_SCCS and not lint */
36*84d9c625SLionel Sambuc 
37*84d9c625SLionel Sambuc #if defined(SOFTFLOAT) || defined(__ARM_EABI__)
38*84d9c625SLionel Sambuc #include "softfloat/softfloat-for-gcc.h"
39*84d9c625SLionel Sambuc #endif
40*84d9c625SLionel Sambuc 
41*84d9c625SLionel Sambuc #include <machine/ieee.h>
42*84d9c625SLionel Sambuc 
43*84d9c625SLionel Sambuc double __floatunsidf(uint32_t);
44*84d9c625SLionel Sambuc 
45*84d9c625SLionel Sambuc /*
46*84d9c625SLionel Sambuc  * Convert (unsigned) int to double.
47*84d9c625SLionel Sambuc  */
48*84d9c625SLionel Sambuc double
__floatunsidf(uint32_t x)49*84d9c625SLionel Sambuc __floatunsidf(uint32_t x)
50*84d9c625SLionel Sambuc {
51*84d9c625SLionel Sambuc 	union ieee_double_u u;
52*84d9c625SLionel Sambuc 
53*84d9c625SLionel Sambuc 	if (x == 0)
54*84d9c625SLionel Sambuc 		return 0.0;
55*84d9c625SLionel Sambuc 	if (x == 1)
56*84d9c625SLionel Sambuc 		return 1.0;
57*84d9c625SLionel Sambuc 
58*84d9c625SLionel Sambuc 	u_int l = __builtin_clz(x);
59*84d9c625SLionel Sambuc 	x <<= (l + 1);	/* clear implicit bit */
60*84d9c625SLionel Sambuc 
61*84d9c625SLionel Sambuc 	u.dblu_sign = 0;
62*84d9c625SLionel Sambuc 	u.dblu_exp = DBL_EXP_BIAS + 31 - l;
63*84d9c625SLionel Sambuc 	u.dblu_frach = x >> (32 - DBL_FRACHBITS);
64*84d9c625SLionel Sambuc 	u.dblu_fracl = x << (32 - DBL_FRACHBITS);
65*84d9c625SLionel Sambuc 
66*84d9c625SLionel Sambuc 	return u.dblu_d;
67*84d9c625SLionel Sambuc }
68