77b9bd9c49
Generic versions of __find_first_bit and __find_first_zero_bit are introduced as simplified versions of __find_next_bit and __find_next_zero_bit. Their compilation and use are guarded by a new config variable GENERIC_FIND_FIRST_BIT. The generic versions of find_first_bit and find_first_zero_bit are implemented in terms of the newly introduced __find_first_bit and __find_first_zero_bit. This patch does not remove the i386-specific implementation, but it does switch i386 to use the generic functions by setting GENERIC_FIND_FIRST_BIT=y for X86_32. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
89 lines
2.0 KiB
C
89 lines
2.0 KiB
C
#ifndef _I386_BITOPS_H
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#define _I386_BITOPS_H
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/*
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* Copyright 1992, Linus Torvalds.
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*/
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#ifndef CONFIG_GENERIC_FIND_FIRST_BIT
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/**
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* find_first_zero_bit - find the first zero bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first zero bit, not the number of the byte
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* containing a bit.
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*/
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static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
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{
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int d0, d1, d2;
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int res;
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if (!size)
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return 0;
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/* This looks at memory.
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* Mark it volatile to tell gcc not to move it around
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*/
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asm volatile("movl $-1,%%eax\n\t"
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"xorl %%edx,%%edx\n\t"
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"repe; scasl\n\t"
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"je 1f\n\t"
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"xorl -4(%%edi),%%eax\n\t"
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"subl $4,%%edi\n\t"
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"bsfl %%eax,%%edx\n"
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"1:\tsubl %%ebx,%%edi\n\t"
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"shll $3,%%edi\n\t"
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"addl %%edi,%%edx"
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: "=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
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: "1" ((size + 31) >> 5), "2" (addr),
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"b" (addr) : "memory");
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return res;
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}
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/**
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* find_first_bit - find the first set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit number of the first set bit, not the number of the byte
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* containing a bit.
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*/
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static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
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{
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unsigned x = 0;
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while (x < size) {
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unsigned long val = *addr++;
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if (val)
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return __ffs(val) + x;
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x += sizeof(*addr) << 3;
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}
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return x;
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}
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#endif
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#ifdef __KERNEL__
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#include <asm-generic/bitops/sched.h>
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#include <asm-generic/bitops/hweight.h>
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#endif /* __KERNEL__ */
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#include <asm-generic/bitops/fls64.h>
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#ifdef __KERNEL__
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#include <asm-generic/bitops/ext2-non-atomic.h>
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#define ext2_set_bit_atomic(lock, nr, addr) \
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test_and_set_bit((nr), (unsigned long *)(addr))
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#define ext2_clear_bit_atomic(lock, nr, addr) \
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test_and_clear_bit((nr), (unsigned long *)(addr))
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#include <asm-generic/bitops/minix.h>
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#endif /* __KERNEL__ */
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#endif /* _I386_BITOPS_H */
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