mirror of
https://github.com/torvalds/linux.git
synced 2024-11-12 07:01:57 +00:00
64af4e0da4
Need to move the bitmap.[ch] things from tools/perf/ to tools/lib, will be done in the next patches. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: George Spelvin <linux@horizon.com Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Wang Nan <wangnan0@huawei.com> Cc: Yury Norov <yury.norov@gmail.com> Link: http://lkml.kernel.org/n/tip-5fys65wkd7gu8j7a7xgukc5t@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/* bit search implementation
|
|
*
|
|
* Copied from lib/find_bit.c to tools/lib/find_bit.c
|
|
*
|
|
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* Copyright (C) 2008 IBM Corporation
|
|
* 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au>
|
|
* (Inspired by David Howell's find_next_bit implementation)
|
|
*
|
|
* Rewritten by Yury Norov <yury.norov@gmail.com> to decrease
|
|
* size and improve performance, 2015.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/bitops.h>
|
|
#include <linux/bitmap.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#if !defined(find_next_bit)
|
|
|
|
/*
|
|
* This is a common helper function for find_next_bit and
|
|
* find_next_zero_bit. The difference is the "invert" argument, which
|
|
* is XORed with each fetched word before searching it for one bits.
|
|
*/
|
|
static unsigned long _find_next_bit(const unsigned long *addr,
|
|
unsigned long nbits, unsigned long start, unsigned long invert)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
if (!nbits || start >= nbits)
|
|
return nbits;
|
|
|
|
tmp = addr[start / BITS_PER_LONG] ^ invert;
|
|
|
|
/* Handle 1st word. */
|
|
tmp &= BITMAP_FIRST_WORD_MASK(start);
|
|
start = round_down(start, BITS_PER_LONG);
|
|
|
|
while (!tmp) {
|
|
start += BITS_PER_LONG;
|
|
if (start >= nbits)
|
|
return nbits;
|
|
|
|
tmp = addr[start / BITS_PER_LONG] ^ invert;
|
|
}
|
|
|
|
return min(start + __ffs(tmp), nbits);
|
|
}
|
|
#endif
|
|
|
|
#ifndef find_next_bit
|
|
/*
|
|
* Find the next set bit in a memory region.
|
|
*/
|
|
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
|
|
unsigned long offset)
|
|
{
|
|
return _find_next_bit(addr, size, offset, 0UL);
|
|
}
|
|
#endif
|
|
|
|
#ifndef find_first_bit
|
|
/*
|
|
* Find the first set bit in a memory region.
|
|
*/
|
|
unsigned long find_first_bit(const unsigned long *addr, unsigned long size)
|
|
{
|
|
unsigned long idx;
|
|
|
|
for (idx = 0; idx * BITS_PER_LONG < size; idx++) {
|
|
if (addr[idx])
|
|
return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size);
|
|
}
|
|
|
|
return size;
|
|
}
|
|
#endif
|