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1c54d77078
This unifies the set/clear/test bit functions of asm/bitops.h. I have not attempted to merge the bit-finding functions, since they rely on the machine word size and can't be easily restructured to work generically without a lot of #ifdefs. In particular, the 64-bit code can assume the presence of conditional move instructions, whereas 32-bit needs to be more careful. The inline assembly for the bit operations has been changed to remove explicit sizing hints on the instructions, so the assembler will pick the appropriate instruction forms depending on the architecture and the context. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Andi Kleen <ak@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
164 lines
3.6 KiB
C
164 lines
3.6 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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/**
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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. Mark it volatile to tell gcc not to move it around */
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__asm__ __volatile__(
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"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), "b" (addr) : "memory");
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return res;
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}
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/**
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* find_next_zero_bit - find the first zero bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bit number to start searching at
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* @size: The maximum size to search
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*/
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int find_next_zero_bit(const unsigned long *addr, int size, int offset);
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/**
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* __ffs - find first bit in word.
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* @word: The word to search
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*
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* Undefined if no bit exists, so code should check against 0 first.
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*/
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static inline unsigned long __ffs(unsigned long word)
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{
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__asm__("bsfl %1,%0"
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:"=r" (word)
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:"rm" (word));
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return word;
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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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/**
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* find_next_bit - find the first set bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bit number to start searching at
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* @size: The maximum size to search
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*/
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int find_next_bit(const unsigned long *addr, int size, int offset);
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/**
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* ffz - find first zero in word.
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* @word: The word to search
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*
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* Undefined if no zero exists, so code should check against ~0UL first.
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*/
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static inline unsigned long ffz(unsigned long word)
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{
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__asm__("bsfl %1,%0"
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:"=r" (word)
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:"r" (~word));
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return word;
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}
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#ifdef __KERNEL__
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#include <asm-generic/bitops/sched.h>
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/**
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* 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 the above ffz() (man ffs).
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*/
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static inline int ffs(int x)
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{
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int r;
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__asm__("bsfl %1,%0\n\t"
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"jnz 1f\n\t"
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"movl $-1,%0\n"
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"1:" : "=r" (r) : "rm" (x));
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return r+1;
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}
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/**
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* fls - find last 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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*/
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static inline int fls(int x)
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{
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int r;
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__asm__("bsrl %1,%0\n\t"
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"jnz 1f\n\t"
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"movl $-1,%0\n"
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"1:" : "=r" (r) : "rm" (x));
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return r+1;
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}
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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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