| /* 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> |
| |
| #ifndef find_last_bit |
| |
| 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); |
| |
| #endif |