1/*	$NetBSD: fpu_int.c,v 1.10 2011/07/18 14:11:27 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 1.10 2011/07/18 14:11:27 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 */
42struct fpn *
43fpu_intrz(struct fpemu *fe)
44{
45	register struct fpn *x = &fe->fe_f2;
46	register 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 */
77struct fpn *
78fpu_int(struct fpemu *fe)
79{
80	register struct fpn *x = &fe->fe_f2;
81	register 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