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cb4ede9261
There's code duplication between the fallback implementation for bitops __ffs/__fls/ffs/fls API and the generic C implementation in include/asm-generic/bitops/. To avoid this duplication, this patch renames the generic C implementation by adding a "generic_" prefix to them, then we can use these generic APIs as fallback. Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Xiao Wang <xiao.w.wang@intel.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Link: https://lore.kernel.org/r/20231112094421.4014931-1-xiao.w.wang@intel.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
48 lines
1,010 B
C
48 lines
1,010 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_BITOPS___FLS_H_
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#define _ASM_GENERIC_BITOPS___FLS_H_
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#include <asm/types.h>
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/**
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* generic___fls - find last (most-significant) set bit in a long word
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* @word: the word to search
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*
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* Undefined if no set bit exists, so code should check against 0 first.
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*/
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static __always_inline unsigned long generic___fls(unsigned long word)
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{
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int num = BITS_PER_LONG - 1;
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#if BITS_PER_LONG == 64
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if (!(word & (~0ul << 32))) {
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num -= 32;
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word <<= 32;
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}
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#endif
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if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
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num -= 16;
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word <<= 16;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
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num -= 8;
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word <<= 8;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
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num -= 4;
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word <<= 4;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
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num -= 2;
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word <<= 2;
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}
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if (!(word & (~0ul << (BITS_PER_LONG-1))))
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num -= 1;
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return num;
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}
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#ifndef __HAVE_ARCH___FLS
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#define __fls(word) generic___fls(word)
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#endif
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#endif /* _ASM_GENERIC_BITOPS___FLS_H_ */
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