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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>
46 lines
761 B
C
46 lines
761 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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/**
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* generic_fls - find last (most-significant) bit set
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* @x: the word to search
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*
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* This is defined the same way as ffs.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static __always_inline int generic_fls(unsigned int x)
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{
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int r = 32;
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if (!x)
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return 0;
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if (!(x & 0xffff0000u)) {
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x <<= 16;
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r -= 16;
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}
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if (!(x & 0xff000000u)) {
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x <<= 8;
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r -= 8;
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}
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if (!(x & 0xf0000000u)) {
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x <<= 4;
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r -= 4;
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}
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if (!(x & 0xc0000000u)) {
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x <<= 2;
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r -= 2;
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}
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if (!(x & 0x80000000u)) {
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x <<= 1;
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r -= 1;
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}
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return r;
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}
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#ifndef __HAVE_ARCH_FLS
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#define fls(x) generic_fls(x)
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#endif
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#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */
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