FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/include/sys/bitops.h

     /*
      * CDDL HEADER START
      *
      * The contents of this file are subject to the terms of the
      * Common Development and Distribution License (the "License").
      * You may not use this file except in compliance with the License.
      *
      * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      * or https://opensource.org/licenses/CDDL-1.0.
     * See the License for the specific language governing permissions
     * and limitations under the License.
     *
     * When distributing Covered Code, include this CDDL HEADER in each
     * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     * If applicable, add the following below this CDDL HEADER, with the
     * fields enclosed by brackets "[]" replaced with your own identifying
     * information: Portions Copyright [yyyy] [name of copyright owner]
     *
     * CDDL HEADER END
     */
    /*
     * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
     * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
     * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
     * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
     * Copyright 2013 Saso Kiselkov. All rights reserved.
     * Copyright (c) 2014 Integros [integros.com]
     * Copyright 2017 Joyent, Inc.
     * Copyright (c) 2017 Datto Inc.
     */
    
    #ifndef _SYS_BITOPS_H
    #define _SYS_BITOPS_H
    
    #include <sys/zfs_context.h>
    
    #ifdef  __cplusplus
    extern "C" {
    #endif
    
    /*
     * General-purpose 32-bit and 64-bit bitfield encodings.
     */
    #define BF32_DECODE(x, low, len)        P2PHASE((x) >> (low), 1U << (len))
    #define BF64_DECODE(x, low, len)        P2PHASE((x) >> (low), 1ULL << (len))
    #define BF32_ENCODE(x, low, len)        (P2PHASE((x), 1U << (len)) << (low))
    #define BF64_ENCODE(x, low, len)        (P2PHASE((x), 1ULL << (len)) << (low))
    
    #define BF32_GET(x, low, len)           BF32_DECODE(x, low, len)
    #define BF64_GET(x, low, len)           BF64_DECODE(x, low, len)
    
    #define BF32_SET(x, low, len, val) do { \
            ASSERT3U(val, <, 1U << (len)); \
            ASSERT3U(low + len, <=, 32); \
            (x) ^= BF32_ENCODE((x >> low) ^ (val), low, len); \
    } while (0)
    
    #define BF64_SET(x, low, len, val) do { \
            ASSERT3U(val, <, 1ULL << (len)); \
            ASSERT3U(low + len, <=, 64); \
            ((x) ^= BF64_ENCODE((x >> low) ^ (val), low, len)); \
    } while (0)
    
    #define BF32_GET_SB(x, low, len, shift, bias)   \
            ((BF32_GET(x, low, len) + (bias)) << (shift))
    #define BF64_GET_SB(x, low, len, shift, bias)   \
            ((BF64_GET(x, low, len) + (bias)) << (shift))
    
    /*
     * We use ASSERT3U instead of ASSERT in these macros to prevent a lint error in
     * the case where val is a constant.  We can't fix ASSERT because it's used as
     * an expression in several places in the kernel.
     */
    #define BF32_SET_SB(x, low, len, shift, bias, val) do { \
            ASSERT3U(IS_P2ALIGNED(val, 1U << shift), !=, B_FALSE); \
            ASSERT3S((val) >> (shift), >=, bias); \
            BF32_SET(x, low, len, ((val) >> (shift)) - (bias)); \
    } while (0)
    #define BF64_SET_SB(x, low, len, shift, bias, val) do { \
            ASSERT3U(IS_P2ALIGNED(val, 1ULL << shift), !=, B_FALSE); \
            ASSERT3S((val) >> (shift), >=, bias); \
            BF64_SET(x, low, len, ((val) >> (shift)) - (bias)); \
    } while (0)
    
    #ifdef  __cplusplus
    }
    #endif
    
    #endif /* _SYS_BITOPS_H */

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