xref: /titanic_41/usr/src/lib/libc/sparc/fp/_Q_itoq.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
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 #ifdef __sparcv9
32 
33 /*
34  * _Qp_itoq(pz, x) sets *pz = (long double)x.
35  */
36 void
_Qp_itoq(union longdouble * pz,int x)37 _Qp_itoq(union longdouble *pz, int x)
38 
39 #else
40 
41 /*
42  * _Q_itoq(x) returns (long double)x.
43  */
44 union longdouble
45 _Q_itoq(int x)
46 
47 #endif /* __sparcv9 */
48 
49 {
50 #ifndef __sparcv9
51 	union longdouble	z;
52 #endif
53 	unsigned int		s, e;
54 
55 	/* extract the sign */
56 	s = 0;
57 	if (x < 0) {
58 		if ((unsigned) x == 0x80000000) {
59 			/* largest negative int */
60 			Z.l.msw = 0xc01e0000;
61 			Z.l.frac2 = Z.l.frac3 = Z.l.frac4 = 0;
62 			QUAD_RETURN(Z);
63 		}
64 		x = -x;
65 		s = 0x80000000;
66 	} else if (x == 0) {
67 		Z.l.msw = Z.l.frac2 = Z.l.frac3 = Z.l.frac4 = 0;
68 		QUAD_RETURN(Z);
69 	}
70 
71 	/* find the most significant bit */
72 	for (e = 30; (x & (1 << e)) == 0; e--)
73 		;
74 
75 	if (e > 16) {
76 		Z.l.msw = ((unsigned) x >> (e - 16)) & 0xffff;
77 		Z.l.frac2 = (unsigned) x << (48 - e);
78 	} else {
79 		Z.l.msw = ((unsigned) x << (16 - e)) & 0xffff;
80 		Z.l.frac2 = 0;
81 	}
82 	Z.l.frac3 = Z.l.frac4 = 0;
83 	Z.l.msw |= s | ((e + 0x3fff) << 16);
84 	QUAD_RETURN(Z);
85 }
86