/* 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 * (Inspired by David Howell's find_next_bit implementation) * * Rewritten by Yury Norov 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 #include #include #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 #ifndef find_first_zero_bit /* * Find the first cleared bit in a memory region. */ unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) { unsigned long idx; for (idx = 0; idx * BITS_PER_LONG < size; idx++) { if (addr[idx] != ~0UL) return min(idx * BITS_PER_LONG + ffz(addr[idx]), size); } return size; } #endif #ifndef find_next_zero_bit unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, unsigned long offset) { return _find_next_bit(addr, size, offset, ~0UL); } #endif ut class='txt' type='search' size='10' name='q' value=''/>
path: root/tools/objtool/special.h
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