1 /* $NetBSD: fpu_int.c,v 1.12 2013/03/19 09:17:17 isaki Exp $ */
2
3 /*
4 * Copyright (c) 1995 Ken Nakata
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * @(#)fpu_int.c
29 */
30
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: fpu_int.c,v 1.12 2013/03/19 09:17:17 isaki Exp $");
33
34 #include <sys/types.h>
35
36 #include <machine/reg.h>
37
38 #include "fpu_arith.h"
39 #include "fpu_emulate.h"
40
41 /* FINTRZ - always round to zero */
42 struct fpn *
fpu_intrz(struct fpemu * fe)43 fpu_intrz(struct fpemu *fe)
44 {
45 struct fpn *x = &fe->fe_f2;
46 int sh, clr, mask, i;
47
48 /* special cases first */
49 if (x->fp_class != FPC_NUM) {
50 return x;
51 }
52 /* when |x| < 1.0 */
53 if (x->fp_exp < 0) {
54 x->fp_class = FPC_ZERO;
55 x->fp_mant[0] = x->fp_mant[1] = x->fp_mant[2] = 0;
56 return x;
57 }
58
59 /* real work */
60 sh = FP_NMANT - 1 - x->fp_exp;
61 if (sh <= 0) {
62 return x;
63 }
64
65 clr = 2 - sh / 32;
66 mask = (0xffffffff << (sh % 32));
67
68 for (i = 2; i > clr; i--) {
69 x->fp_mant[i] = 0;
70 }
71 x->fp_mant[i] &= mask;
72
73 return x;
74 }
75
76 /* FINT */
77 struct fpn *
fpu_int(struct fpemu * fe)78 fpu_int(struct fpemu *fe)
79 {
80 struct fpn *x = &fe->fe_f2;
81 int rsh;
82
83 /* special cases first */
84 if (x->fp_class != FPC_NUM) {
85 return x;
86 }
87
88 rsh = FP_NMANT - 1 - x->fp_exp;
89 if (rsh <= FP_NG) {
90 return x;
91 }
92
93 /* shift to the right */
94 x->fp_exp = 0;
95 fpu_shr(x, rsh - FP_NG);
96
97 /* round according to FPCR round mode */
98 fpu_round(fe, x);
99
100 /* shift it back to the left */
101 x->fp_exp = FP_NMANT - 1;
102 fpu_norm(x);
103
104 return x;
105 }
106