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include: sbi_bitops: More useful bit operations
This patch extends our bit operation library with mechanism to: 1. Iteratively traverse bits 2. Set bit 3. Clear bit 4. Change bit 5. ... other helpful functions ... Most the above is adopted from Xvisor sources. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Anup Patel
Anup Patel
parent
00d332bbe7
commit
a148996a7f
3 changed files with 340 additions and 2 deletions
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@ -4,7 +4,7 @@
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* Copyright (c) 2019 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Atish Patra<atish.patra@wdc.com>
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* Atish Patra <atish.patra@wdc.com>
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*/
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#ifndef __SBI_BITOPS_H__
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@ -25,8 +25,16 @@
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#define INSERT_FIELD(val, which, fieldval) \
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(((val) & ~(which)) | ((fieldval) * ((which) & ~((which)-1))))
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#define BITS_TO_LONGS(nbits) (((nbits) + BITS_PER_LONG - 1) / \
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BITS_PER_LONG)
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#define BIT(nr) (1UL << (nr))
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#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
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#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
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#define BIT_WORD(bit) ((bit) / BITS_PER_LONG)
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#define BIT_WORD_OFFSET(bit) ((bit) & (BITS_PER_LONG - 1))
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#define GENMASK(h, l) \
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(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
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/**
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* ffs - Find first bit set
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@ -184,4 +192,133 @@ static inline unsigned long __fls(unsigned long word)
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return num;
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}
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#define for_each_set_bit(bit, addr, size) \
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for ((bit) = find_first_bit((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_bit((addr), (size), (bit) + 1))
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/* same as for_each_set_bit() but use bit as value to start with */
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#define for_each_set_bit_from(bit, addr, size) \
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for ((bit) = find_next_bit((addr), (size), (bit)); \
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(bit) < (size); \
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(bit) = find_next_bit((addr), (size), (bit) + 1))
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#define for_each_clear_bit(bit, addr, size) \
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for ((bit) = find_first_zero_bit((addr), (size)); \
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(bit) < (size); \
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(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
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/* same as for_each_clear_bit() but use bit as value to start with */
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#define for_each_clear_bit_from(bit, addr, size) \
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for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
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(bit) < (size); \
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(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
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unsigned long find_first_bit(const unsigned long *addr,
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unsigned long size);
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unsigned long find_first_zero_bit(const unsigned long *addr,
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unsigned long size);
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unsigned long find_last_bit(const unsigned long *addr,
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unsigned long size);
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unsigned long find_next_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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unsigned long find_next_zero_bit(const unsigned long *addr,
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unsigned long size,
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unsigned long offset);
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/**
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* __set_bit - Set a bit in memory
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* This function is non-atomic and may be reordered.
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*/
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static inline void __set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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*p |= mask;
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}
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/**
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* __clear_bit - Clear a bit in memory
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* @nr: the bit to clear
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* @addr: the address to start counting from
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*
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* This function is non-atomic and may be reordered.
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*/
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static inline void __clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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*p &= ~mask;
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}
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/**
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* __change_bit - Toggle a bit in memory
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* @nr: the bit to change
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* @addr: the address to start counting from
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*
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* This function is non-atomic and may be reordered.
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*/
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static inline void __change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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*p ^= mask;
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}
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/**
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* __test_and_set_bit - Set a bit and return its old value
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is non-atomic and can be reordered.
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*/
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static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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unsigned long old = *p;
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*p = old | mask;
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return (old & mask) != 0;
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}
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/**
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* __test_and_clear_bit - Clear a bit and return its old value
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* @nr: Bit to clear
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* @addr: Address to count from
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*
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* This operation is non-atomic and can be reordered.
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*/
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static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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unsigned long old = *p;
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*p = old & ~mask;
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return (old & mask) != 0;
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}
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/**
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* __test_bit - Determine whether a bit is set
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* @nr: bit number to test
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* @addr: Address to start counting from
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*
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* This operation is non-atomic and can be reordered.
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*/
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static inline int __test_bit(int nr, const volatile unsigned long *addr)
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{
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return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
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}
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#endif
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@ -12,6 +12,7 @@ libsbi-objs-y += riscv_atomic.o
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libsbi-objs-y += riscv_hardfp.o
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libsbi-objs-y += riscv_locks.o
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libsbi-objs-y += sbi_bitops.o
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libsbi-objs-y += sbi_console.o
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libsbi-objs-y += sbi_ecall.o
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libsbi-objs-y += sbi_ecall_base.o
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200
lib/sbi/sbi_bitops.c
Normal file
200
lib/sbi/sbi_bitops.c
Normal file
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@ -0,0 +1,200 @@
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/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2020 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Atish Patra <atish.patra@wdc.com>
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* Anup Patel <anup.patel@wdc.com>
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*/
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#include <sbi/sbi_bitops.h>
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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/**
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* find_first_bit - find the first set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first set bit.
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*/
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unsigned long find_first_bit(const unsigned long *addr,
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unsigned long size)
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{
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const unsigned long *p = addr;
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unsigned long result = 0;
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unsigned long tmp;
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while (size & ~(BITS_PER_LONG-1)) {
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if ((tmp = *(p++)))
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goto found;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = (*p) & (~0UL >> (BITS_PER_LONG - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found:
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return result + __ffs(tmp);
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}
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/**
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* find_first_zero_bit - find the first cleared bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first cleared bit.
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*/
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unsigned long find_first_zero_bit(const unsigned long *addr,
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unsigned long size)
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{
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const unsigned long *p = addr;
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unsigned long result = 0;
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unsigned long tmp;
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while (size & ~(BITS_PER_LONG-1)) {
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if (~(tmp = *(p++)))
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goto found;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = (*p) | (~0UL << size);
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. */
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found:
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return result + ffz(tmp);
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}
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/**
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* find_last_bit - find the last set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first set bit, or size.
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*/
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unsigned long find_last_bit(const unsigned long *addr,
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unsigned long size)
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{
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unsigned long words;
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unsigned long tmp;
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/* Start at final word. */
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words = size / BITS_PER_LONG;
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/* Partial final word? */
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if (size & (BITS_PER_LONG-1)) {
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tmp = (addr[words] & (~0UL >> (BITS_PER_LONG
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- (size & (BITS_PER_LONG-1)))));
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if (tmp)
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goto found;
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}
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while (words) {
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tmp = addr[--words];
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if (tmp) {
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found:
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return words * BITS_PER_LONG + __fls(tmp);
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}
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}
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/* Not found */
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return size;
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}
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/**
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* find_next_bit - find the next set bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The bitmap size in bits
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*/
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unsigned long find_next_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset)
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{
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const unsigned long *p = addr + BITOP_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG-1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset %= BITS_PER_LONG;
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG-1)) {
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if ((tmp = *(p++)))
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp &= (~0UL >> (BITS_PER_LONG - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found_middle:
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return result + __ffs(tmp);
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}
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/**
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* find_next_zero_bit - find the next cleared bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The bitmap size in bits
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*/
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unsigned long find_next_zero_bit(const unsigned long *addr,
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unsigned long size,
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unsigned long offset)
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{
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const unsigned long *p = addr + BITOP_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG-1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset %= BITS_PER_LONG;
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (BITS_PER_LONG - offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG-1)) {
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if (~(tmp = *(p++)))
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. */
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found_middle:
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return result + ffz(tmp);
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}
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