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 2003 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29#include <sys/types.h>
30#include <sys/bitmap.h>
31#include <assert.h>
32#include <strings.h>
33#include <stdlib.h>
34
35#include <dt_regset.h>
36
37dt_regset_t *
38dt_regset_create(ulong_t size)
39{
40	ulong_t n = BT_BITOUL(size + 1); /* + 1 for %r0 */
41	dt_regset_t *drp = malloc(sizeof (dt_regset_t));
42
43	if (drp == NULL)
44		return (NULL);
45
46	drp->dr_bitmap = malloc(sizeof (ulong_t) * n);
47	drp->dr_size = size + 1;
48
49	if (drp->dr_bitmap == NULL) {
50		dt_regset_destroy(drp);
51		return (NULL);
52	}
53
54	bzero(drp->dr_bitmap, sizeof (ulong_t) * n);
55	return (drp);
56}
57
58void
59dt_regset_destroy(dt_regset_t *drp)
60{
61	free(drp->dr_bitmap);
62	free(drp);
63}
64
65void
66dt_regset_reset(dt_regset_t *drp)
67{
68	bzero(drp->dr_bitmap, sizeof (ulong_t) * BT_BITOUL(drp->dr_size));
69}
70
71int
72dt_regset_alloc(dt_regset_t *drp)
73{
74	ulong_t nbits = drp->dr_size - 1;
75	ulong_t maxw = nbits >> BT_ULSHIFT;
76	ulong_t wx;
77
78	for (wx = 0; wx <= maxw; wx++) {
79		if (drp->dr_bitmap[wx] != ~0UL)
80			break;
81	}
82
83	if (wx <= maxw) {
84		ulong_t maxb = (wx == maxw) ? nbits & BT_ULMASK : BT_NBIPUL - 1;
85		ulong_t word = drp->dr_bitmap[wx];
86		ulong_t bit, bx;
87		int reg;
88
89		for (bit = 1, bx = 0; bx <= maxb; bx++, bit <<= 1) {
90			if ((word & bit) == 0) {
91				reg = (int)((wx << BT_ULSHIFT) | bx);
92				BT_SET(drp->dr_bitmap, reg);
93				return (reg);
94			}
95		}
96	}
97
98	return (-1); /* no available registers */
99}
100
101void
102dt_regset_free(dt_regset_t *drp, int reg)
103{
104	assert(reg > 0 && reg < drp->dr_size);
105	assert(BT_TEST(drp->dr_bitmap, reg) != 0);
106	BT_CLEAR(drp->dr_bitmap, reg);
107}
108