xref: /illumos-gate/usr/src/lib/libc/sparcv9/fp/_Qp_uxtoq.c (revision a386cc11a86ecb60f5a48078d22c1500e2ad003e)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "quad.h"
30 
31 /*
32  * _Qp_uxtoq(pz, x) sets *pz = (long double)x.
33  */
34 void
35 _Qp_uxtoq(union longdouble *pz, unsigned long x)
36 {
37 	unsigned int	e;
38 
39 	/* test for zero */
40 	if (x == 0) {
41 		Z.l.msw = Z.l.frac2 = Z.l.frac3 = Z.l.frac4 = 0;
42 		QUAD_RETURN(Z);
43 	}
44 
45 	/* find the most significant bit */
46 	for (e = 63; (x & (1l << e)) == 0; e--)
47 		;
48 
49 	if (e > 48) {
50 		Z.l.msw = (x >> (e - 16)) & 0xffff;
51 		Z.l.frac2 = x >> (e - 48);
52 		Z.l.frac3 = x << (80 - e);
53 	} else if (e > 16) {
54 		Z.l.msw = (x >> (e - 16)) & 0xffff;
55 		Z.l.frac2 = x << (48 - e);
56 		Z.l.frac3 = 0;
57 	} else {
58 		Z.l.msw = (x << (16 - e)) & 0xffff;
59 		Z.l.frac2 = Z.l.frac3 = 0;
60 	}
61 	Z.l.frac4 = 0;
62 	Z.l.msw |= ((e + 0x3fff) << 16);
63 	QUAD_RETURN(Z);
64 }
65