include/sys/bitops.h

   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 https://opensource.org/licenses/CDDL-1.0.
  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
  38 extern "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 } 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 } 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.
  73  */
  74 #define BF32_SET_SB(x, low, len, shift, bias, val) do { \
  75         ASSERT3U(IS_P2ALIGNED(val, 1U << shift), !=, B_FALSE); \
  76         ASSERT3S((val) >> (shift), >=, bias); \
  77         BF32_SET(x, low, len, ((val) >> (shift)) - (bias)); \
  78 } while (0)
  79 #define BF64_SET_SB(x, low, len, shift, bias, val) do { \
  80         ASSERT3U(IS_P2ALIGNED(val, 1ULL << shift), !=, B_FALSE); \
  81         ASSERT3S((val) >> (shift), >=, bias); \
  82         BF64_SET(x, low, len, ((val) >> (shift)) - (bias)); \
  83 } while (0)
  84
  85 #ifdef  __cplusplus
  86 }
  87 #endif
  88
  89 #endif /* _SYS_BITOPS_H */