2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
125 lines
3.0 KiB
C
125 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* bit search implementation
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*
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* Copied from lib/find_bit.c to tools/lib/find_bit.c
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* Copyright (C) 2008 IBM Corporation
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* 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au>
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* (Inspired by David Howell's find_next_bit implementation)
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*
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* Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
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* size and improve performance, 2015.
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*/
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#include <linux/bitops.h>
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#include <linux/bitmap.h>
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#include <linux/kernel.h>
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#if !defined(find_next_bit) || !defined(find_next_zero_bit) || \
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!defined(find_next_and_bit)
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/*
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* This is a common helper function for find_next_bit, find_next_zero_bit, and
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* find_next_and_bit. The differences are:
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* - The "invert" argument, which is XORed with each fetched word before
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* searching it for one bits.
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* - The optional "addr2", which is anded with "addr1" if present.
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*/
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static inline unsigned long _find_next_bit(const unsigned long *addr1,
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const unsigned long *addr2, unsigned long nbits,
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unsigned long start, unsigned long invert)
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{
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unsigned long tmp;
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if (unlikely(start >= nbits))
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return nbits;
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tmp = addr1[start / BITS_PER_LONG];
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if (addr2)
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tmp &= addr2[start / BITS_PER_LONG];
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tmp ^= invert;
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/* Handle 1st word. */
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tmp &= BITMAP_FIRST_WORD_MASK(start);
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start = round_down(start, BITS_PER_LONG);
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while (!tmp) {
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start += BITS_PER_LONG;
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if (start >= nbits)
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return nbits;
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tmp = addr1[start / BITS_PER_LONG];
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if (addr2)
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tmp &= addr2[start / BITS_PER_LONG];
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tmp ^= invert;
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}
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return min(start + __ffs(tmp), nbits);
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}
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#endif
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#ifndef find_next_bit
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/*
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* Find the next set bit in a memory region.
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*/
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unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
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unsigned long offset)
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{
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return _find_next_bit(addr, NULL, size, offset, 0UL);
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}
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#endif
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#ifndef find_first_bit
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/*
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* Find the first set bit in a memory region.
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*/
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unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
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{
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unsigned long idx;
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for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
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if (addr[idx])
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return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
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}
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return size;
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}
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#endif
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#ifndef find_first_zero_bit
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/*
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* Find the first cleared bit in a memory region.
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*/
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unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size)
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{
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unsigned long idx;
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for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
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if (addr[idx] != ~0UL)
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return min(idx * BITS_PER_LONG + ffz(addr[idx]), size);
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}
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return size;
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}
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#endif
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#ifndef find_next_zero_bit
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unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
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unsigned long offset)
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{
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return _find_next_bit(addr, NULL, size, offset, ~0UL);
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}
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#endif
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#ifndef find_next_and_bit
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unsigned long find_next_and_bit(const unsigned long *addr1,
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const unsigned long *addr2, unsigned long size,
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unsigned long offset)
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{
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return _find_next_bit(addr1, addr2, size, offset, 0UL);
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}
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#endif
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