mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 04:34:11 +08:00
ab53d472e7
Impact: New API As the name suggests. For the moment everyone uses the generic one. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
/* 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);
|