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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
24 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 * Copyright 2013 Saso Kiselkov. All rights reserved.
27 * Copyright (c) 2014 Integros [integros.com]
28 * Copyright 2017 Joyent, Inc.
29 * Copyright (c) 2017 Datto Inc.
30 */
31
32#ifndef _SYS_BITOPS_H
33#define	_SYS_BITOPS_H
34
35#include <sys/zfs_context.h>
36
37#ifdef	__cplusplus
38extern "C" {
39#endif
40
41/*
42 * General-purpose 32-bit and 64-bit bitfield encodings.
43 */
44#define	BF32_DECODE(x, low, len)	P2PHASE((x) >> (low), 1U << (len))
45#define	BF64_DECODE(x, low, len)	P2PHASE((x) >> (low), 1ULL << (len))
46#define	BF32_ENCODE(x, low, len)	(P2PHASE((x), 1U << (len)) << (low))
47#define	BF64_ENCODE(x, low, len)	(P2PHASE((x), 1ULL << (len)) << (low))
48
49#define	BF32_GET(x, low, len)		BF32_DECODE(x, low, len)
50#define	BF64_GET(x, low, len)		BF64_DECODE(x, low, len)
51
52#define	BF32_SET(x, low, len, val) do { \
53	ASSERT3U(val, <, 1U << (len)); \
54	ASSERT3U(low + len, <=, 32); \
55	(x) ^= BF32_ENCODE((x >> low) ^ (val), low, len); \
56_NOTE(CONSTCOND) } while (0)
57
58#define	BF64_SET(x, low, len, val) do { \
59	ASSERT3U(val, <, 1ULL << (len)); \
60	ASSERT3U(low + len, <=, 64); \
61	((x) ^= BF64_ENCODE((x >> low) ^ (val), low, len)); \
62_NOTE(CONSTCOND) } while (0)
63
64#define	BF32_GET_SB(x, low, len, shift, bias)	\
65	((BF32_GET(x, low, len) + (bias)) << (shift))
66#define	BF64_GET_SB(x, low, len, shift, bias)	\
67	((BF64_GET(x, low, len) + (bias)) << (shift))
68
69/*
70 * We use ASSERT3U instead of ASSERT in these macros to prevent a lint error in
71 * the case where val is a constant.  We can't fix ASSERT because it's used as
72 * an expression in several places in the kernel; as a result, changing it to
73 * the do{} while() syntax to allow us to _NOTE the CONSTCOND is not an option.
74 */
75#define	BF32_SET_SB(x, low, len, shift, bias, val) do { \
76	ASSERT3U(IS_P2ALIGNED(val, 1U << shift), !=, B_FALSE); \
77	ASSERT3S((val) >> (shift), >=, bias); \
78	BF32_SET(x, low, len, ((val) >> (shift)) - (bias)); \
79_NOTE(CONSTCOND) } while (0)
80#define	BF64_SET_SB(x, low, len, shift, bias, val) do { \
81	ASSERT3U(IS_P2ALIGNED(val, 1ULL << shift), !=, B_FALSE); \
82	ASSERT3S((val) >> (shift), >=, bias); \
83	BF64_SET(x, low, len, ((val) >> (shift)) - (bias)); \
84_NOTE(CONSTCOND) } while (0)
85
86#ifdef	__cplusplus
87}
88#endif
89
90#endif /* _SYS_BITOPS_H */
91