mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 04:38:03 +00:00
9c313ccdfc
Change the return types of bitops functions (ffs, fls, and fns) from long to int. The expected return values are in the range [0, 64], for which int is sufficient. Additionally, int aligns well with the return types of the corresponding __builtin_* functions, potentially reducing overall type conversions. Many of the existing bitops functions already return an int and don't need to be changed. The bitops functions in arch/ should be considered separately. Adjust some return variables to match the function return types. With GCC 13 and defconfig, these changes reduced the size of a test kernel image by 5,432 bytes on arm64 and by 248 bytes on riscv; there were no changes in size on x86_64, powerpc, or m68k. Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
49 lines
1018 B
C
49 lines
1018 B
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_GENERIC_BITOPS___FLS_H_
|
|
#define _ASM_GENERIC_BITOPS___FLS_H_
|
|
|
|
#include <asm/types.h>
|
|
|
|
/**
|
|
* generic___fls - find last (most-significant) set bit in a long word
|
|
* @word: the word to search
|
|
*
|
|
* Undefined if no set bit exists, so code should check against 0 first.
|
|
*/
|
|
static __always_inline unsigned int generic___fls(unsigned long word)
|
|
{
|
|
unsigned int num = BITS_PER_LONG - 1;
|
|
|
|
#if BITS_PER_LONG == 64
|
|
if (!(word & (~0ul << 32))) {
|
|
num -= 32;
|
|
word <<= 32;
|
|
}
|
|
#endif
|
|
if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
|
|
num -= 16;
|
|
word <<= 16;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
|
|
num -= 8;
|
|
word <<= 8;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
|
|
num -= 4;
|
|
word <<= 4;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
|
|
num -= 2;
|
|
word <<= 2;
|
|
}
|
|
if (!(word & (~0ul << (BITS_PER_LONG-1))))
|
|
num -= 1;
|
|
return num;
|
|
}
|
|
|
|
#ifndef __HAVE_ARCH___FLS
|
|
#define __fls(word) generic___fls(word)
|
|
#endif
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
|