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/* $NetBSD: bitops.h,v 1.11 2021/12/19 01:33:59 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Taylor R. Campbell.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _LINUX_BITOPS_H_
#define _LINUX_BITOPS_H_
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/bitops.h>
#include <machine/limits.h>
#include <lib/libkern/libkern.h>
/*
* Linux __ffs/__ffs64 is zero-based; zero input is undefined. Our
* ffs/ffs64 is one-based; zero input yields zero.
*/
static inline unsigned long
__ffs(unsigned long x)
{
KASSERT(x != 0);
return ffs64(x) - 1;
}
static inline unsigned long
__ffs64(uint64_t x)
{
KASSERT(x != 0);
return ffs64(x) - 1;
}
/*
* Linux fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32, so it matches
* our fls semantics.
*/
static inline int
fls(int x)
{
return fls32(x);
}
static inline unsigned int
hweight8(uint8_t w)
{
return popcount(w & 0xff);
}
static inline unsigned int
hweight16(uint16_t n)
{
return popcount32(n);
}
static inline unsigned int
hweight32(uint32_t n)
{
return popcount32(n);
}
static inline unsigned int
hweight64(uint64_t n)
{
return popcount64(n);
}
static inline int64_t
sign_extend64(uint64_t x, unsigned n)
{
return (int64_t)(x << (63 - n)) >> (63 - n);
}
/*
* XXX Don't define BITS_PER_LONG as sizeof(unsigned long)*CHAR_BIT
* because that won't work in preprocessor conditionals, where it often
* turns up.
*/
#define BITS_PER_BYTE 8
#define BITS_TO_LONGS(n) \
roundup2((n), (sizeof(unsigned long) * CHAR_BIT))
#define BITS_PER_BYTE NBBY
#define BIT(n) ((unsigned long)__BIT(n))
#define BIT_ULL(n) ((unsigned long long)__BIT(n))
#define GENMASK(h,l) ((unsigned long)__BITS(h,l))
#define GENMASK_ULL(h,l)((unsigned long long)__BITS(h,l))
static inline int
test_bit(unsigned int n, const volatile unsigned long *p)
{
const unsigned units = (sizeof(unsigned long) * CHAR_BIT);
return ((p[n / units] & (1UL << (n % units))) != 0);
}
static inline void
__set_bit(unsigned int n, volatile unsigned long *p)
{
const unsigned units = (sizeof(unsigned long) * CHAR_BIT);
p[n / units] |= (1UL << (n % units));
}
static inline void
__clear_bit(unsigned int n, volatile unsigned long *p)
{
const unsigned units = (sizeof(unsigned long) * CHAR_BIT);
p[n / units] &= ~(1UL << (n % units));
}
static inline void
__change_bit(unsigned int n, volatile unsigned long *p)
{
const unsigned units = (sizeof(unsigned long) * CHAR_BIT);
p[n / units] ^= (1UL << (n % units));
}
static inline unsigned long
__test_and_set_bit(unsigned int bit, volatile unsigned long *ptr)
{
const unsigned int units = (sizeof(*ptr) * CHAR_BIT);
volatile unsigned long *const p = &ptr[bit / units];
const unsigned long mask = (1UL << (bit % units));
unsigned long v;
v = *p;
*p |= mask;
return ((v & mask) != 0);
}
static inline unsigned long
__test_and_clear_bit(unsigned int bit, volatile unsigned long *ptr)
{
const unsigned int units = (sizeof(*ptr) * CHAR_BIT);
volatile unsigned long *const p = &ptr[bit / units];
const unsigned long mask = (1UL << (bit % units));
unsigned long v;
v = *p;
*p &= ~mask;
return ((v & mask) != 0);
}
static inline unsigned long
__test_and_change_bit(unsigned int bit, volatile unsigned long *ptr)
{
const unsigned int units = (sizeof(*ptr) * CHAR_BIT);
volatile unsigned long *const p = &ptr[bit / units];
const unsigned long mask = (1UL << (bit % units));
unsigned long v;
v = *p;
*p ^= mask;
return ((v & mask) != 0);
}
static inline unsigned long
__find_next_bit(const unsigned long *ptr, unsigned long nbits,
unsigned long startbit, unsigned long toggle)
{
const size_t bpl = (CHAR_BIT * sizeof(*ptr));
const unsigned long *p = ptr + startbit/bpl;
size_t n = howmany(nbits, bpl);
unsigned long result;
uint64_t word;
/*
* We use ffs64 because NetBSD doesn't have a handy ffsl that
* works on unsigned long. This is a waste on 32-bit systems
* but I'd rather not maintain multiple copies of this -- the
* first version had enough bugs already.
*/
/* Do we need to examine a partial starting word? */
if (startbit % bpl) {
/* Toggle the bits and convert to 64 bits for ffs64. */
word = *p ^ toggle;
/* Clear the low startbit%bpl bits. */
word &= (~0UL << (startbit % bpl));
/* Are any of these bits set now? */
if (word)
goto out;
/* Move past it. */
p++;
n--;
}
/* Find the first word with any bits set. */
for (; n --> 0; p++) {
/* Toggle the bits and convert to 64 bits for ffs64. */
word = *p ^ toggle;
/* Are any of these bits set now? */
if (word)
goto out;
}
/* Nada. */
return nbits;
out:
/* Count how many words we've skipped. */
result = bpl*(p - ptr);
/* Find the first set bit in this word, zero-based. */
result += ffs64(word) - 1;
/* We may have overshot, so clamp down to at most nbits. */
return MIN(result, nbits);
}
static inline unsigned long
find_next_bit(const unsigned long *ptr, unsigned long nbits,
unsigned long startbit)
{
return __find_next_bit(ptr, nbits, startbit, 0);
}
static inline unsigned long
find_first_bit(const unsigned long *ptr, unsigned long nbits)
{
return find_next_bit(ptr, nbits, 0);
}
static inline unsigned long
find_next_zero_bit(const unsigned long *ptr, unsigned long nbits,
unsigned long startbit)
{
return __find_next_bit(ptr, nbits, startbit, ~0UL);
}
static inline unsigned long
find_first_zero_bit(const unsigned long *ptr, unsigned long nbits)
{
return find_next_zero_bit(ptr, nbits, 0);
}
#define for_each_set_bit(BIT, PTR, NBITS) \
for ((BIT) = find_first_bit((PTR), (NBITS)); \
(BIT) < (NBITS); \
(BIT) = find_next_bit((PTR), (NBITS), (BIT) + 1))
#define for_each_clear_bit(BIT, PTR, NBITS) \
for ((BIT) = find_first_zero_bit((PTR), (NBITS)); \
(BIT) < (NBITS); \
(BIT) = find_next_zero_bit((PTR), (NBITS), (BIT) + 1))
#endif /* _LINUX_BITOPS_H_ */
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