1 /* $NetBSD: floatunditf_ieee754.c,v 1.4 2012/08/05 04:28:58 matt Exp $ */
2
3 /*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char sccsid[] = "@(#)floatunsdidf.c 8.1 (Berkeley) 6/4/93";
40 #else
41 __RCSID("$NetBSD: floatunditf_ieee754.c,v 1.4 2012/08/05 04:28:58 matt Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44
45 #ifdef SOFTFLOAT
46 #include "softfloat/softfloat-for-gcc.h"
47 #endif
48
49 #include "quad.h"
50 #ifdef __vax__
51 #error vax does not support a distinct long double
52 #endif
53 #include <machine/ieee.h>
54
55 /*
56 * Convert (unsigned) quad to long double.
57 * This is exactly like floatdidf.c except that negatives never occur.
58 */
59 long double
__floatunditf(u_quad_t x)60 __floatunditf(u_quad_t x)
61 {
62 #if 0
63 long double ld;
64 union uu u;
65
66 u.uq = x;
67 ld = (long double)u.ul[H] * (((int)1 << (INT_BITS - 2)) * 4.0);
68 ld += u.ul[L];
69 return (ld);
70 #else
71 union ieee_ext_u extu;
72 quad_t tmp = x; /* must be signed */
73 unsigned int width = 64;
74 unsigned int bit = 0;
75 quad_t mask = ~(quad_t)0;
76
77 if (x == 0)
78 return 0.0L;
79 if (x == 1)
80 return 1.0L;
81
82 while (mask != 0 && (tmp >= 0)) {
83 width >>= 1;
84 mask <<= width;
85 if ((tmp & mask) == 0) {
86 tmp <<= width;
87 bit += width;
88 }
89 }
90
91 x <<= (bit + 1);
92 extu.extu_sign = 0;
93 extu.extu_exp = EXT_EXP_BIAS + (64 - (bit + 1));
94 extu.extu_frach = (unsigned int)(x >> (64 - EXT_FRACHBITS));
95 x <<= EXT_FRACHBITS;
96 #ifdef EXT_FRACHMBITS
97 extu.extu_frachm =(unsigned int)(x >> (64 - EXT_FRACHMBITS));
98 x <<= EXT_FRACHMBITS;
99 #endif
100 #ifdef EXT_FRACLMBITS
101 extu.extu_fraclm =(unsigned int)(x >> (64 - EXT_FRACLMBITS));
102 x <<= EXT_FRACLMBITS;
103 #endif
104 extu.extu_fracl =(unsigned int)(x >> (64 - EXT_FRACLBITS));
105
106 return extu.extu_ld;
107 #endif
108 }
109