/* find_last_bit.c: fallback find next bit implementation * * Copyright (C) 2008 IBM Corporation * Written by Rusty Russell <rusty@rustcorp.com.au> * (Inspired by David Howell's find_next_bit implementation) * * 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/module.h> #include <asm/types.h> #include <asm/byteorder.h> unsigned long find_last_bit(const unsigned long *addr, unsigned long size) { unsigned long words; unsigned long tmp; /* Start at final word. */ words = size / BITS_PER_LONG; /* Partial final word? */ if (size & (BITS_PER_LONG-1)) { tmp = (addr[words] & (~0UL >> (BITS_PER_LONG - (size & (BITS_PER_LONG-1))))); if (tmp) goto found; } while (words) { tmp = addr[--words]; if (tmp) { found: return words * BITS_PER_LONG + __fls(tmp); } } /* Not found */ return size; } EXPORT_SYMBOL(find_last_bit);