47 lines
722 B
C
47 lines
722 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_BITOPS_FFS_H_
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#define _ASM_GENERIC_BITOPS_FFS_H_
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/**
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* generic_ffs - find first 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
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from ffz (man ffs).
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*/
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static inline int generic_ffs(int x)
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{
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int r = 1;
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if (!x)
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return 0;
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if (!(x & 0xffff)) {
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x >>= 16;
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r += 16;
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}
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if (!(x & 0xff)) {
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x >>= 8;
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r += 8;
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}
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if (!(x & 0xf)) {
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x >>= 4;
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r += 4;
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}
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if (!(x & 3)) {
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x >>= 2;
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r += 2;
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}
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if (!(x & 1)) {
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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_FFS
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#define ffs(x) generic_ffs(x)
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#endif
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#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
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