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![Kumar Gala](/assets/img/avatar_default.png)
fls64, __ilog2_u64, ffs64 are variants that work on an u64, and fls is used to implement them. Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
386 lines
8.5 KiB
C
386 lines
8.5 KiB
C
/*
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* bitops.h: Bit string operations on the ppc
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*/
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#ifndef _PPC_BITOPS_H
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#define _PPC_BITOPS_H
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#include <linux/config.h>
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#include <asm/byteorder.h>
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extern void set_bit(int nr, volatile void *addr);
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extern void clear_bit(int nr, volatile void *addr);
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extern void change_bit(int nr, volatile void *addr);
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extern int test_and_set_bit(int nr, volatile void *addr);
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extern int test_and_clear_bit(int nr, volatile void *addr);
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extern int test_and_change_bit(int nr, volatile void *addr);
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/*
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* Arguably these bit operations don't imply any memory barrier or
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* SMP ordering, but in fact a lot of drivers expect them to imply
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* both, since they do on x86 cpus.
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*/
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#ifdef CONFIG_SMP
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#define SMP_WMB "eieio\n"
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#define SMP_MB "\nsync"
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#else
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#define SMP_WMB
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#define SMP_MB
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#endif /* CONFIG_SMP */
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#define __INLINE_BITOPS 1
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#if __INLINE_BITOPS
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/*
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* These used to be if'd out here because using : "cc" as a constraint
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* resulted in errors from egcs. Things may be OK with gcc-2.95.
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*/
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extern __inline__ void set_bit(int nr, volatile void * addr)
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{
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unsigned long old;
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unsigned long mask = 1 << (nr & 0x1f);
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unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%3\n\
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or %0,%0,%2\n\
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stwcx. %0,0,%3\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc" );
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}
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extern __inline__ void clear_bit(int nr, volatile void *addr)
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{
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unsigned long old;
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unsigned long mask = 1 << (nr & 0x1f);
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unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%3\n\
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andc %0,%0,%2\n\
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stwcx. %0,0,%3\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc");
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}
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extern __inline__ void change_bit(int nr, volatile void *addr)
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{
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unsigned long old;
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unsigned long mask = 1 << (nr & 0x1f);
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unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%3\n\
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xor %0,%0,%2\n\
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stwcx. %0,0,%3\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc");
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}
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extern __inline__ int test_and_set_bit(int nr, volatile void *addr)
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{
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unsigned int old, t;
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unsigned int mask = 1 << (nr & 0x1f);
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volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%4\n\
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or %1,%0,%3\n\
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stwcx. %1,0,%4\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=&r" (t), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc");
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return (old & mask) != 0;
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}
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extern __inline__ int test_and_clear_bit(int nr, volatile void *addr)
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{
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unsigned int old, t;
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unsigned int mask = 1 << (nr & 0x1f);
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volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%4\n\
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andc %1,%0,%3\n\
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stwcx. %1,0,%4\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=&r" (t), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc");
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return (old & mask) != 0;
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}
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extern __inline__ int test_and_change_bit(int nr, volatile void *addr)
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{
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unsigned int old, t;
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unsigned int mask = 1 << (nr & 0x1f);
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volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
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__asm__ __volatile__(SMP_WMB "\
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1: lwarx %0,0,%4\n\
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xor %1,%0,%3\n\
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stwcx. %1,0,%4\n\
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bne 1b"
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SMP_MB
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: "=&r" (old), "=&r" (t), "=m" (*p)
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: "r" (mask), "r" (p), "m" (*p)
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: "cc");
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return (old & mask) != 0;
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}
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#endif /* __INLINE_BITOPS */
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extern __inline__ int test_bit(int nr, __const__ volatile void *addr)
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{
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__const__ unsigned int *p = (__const__ unsigned int *) addr;
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return ((p[nr >> 5] >> (nr & 0x1f)) & 1) != 0;
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}
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/* Return the bit position of the most significant 1 bit in a word */
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/* - the result is undefined when x == 0 */
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extern __inline__ int __ilog2(unsigned int x)
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{
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int lz;
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asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
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return 31 - lz;
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}
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extern __inline__ int ffz(unsigned int x)
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{
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if ((x = ~x) == 0)
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return 32;
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return __ilog2(x & -x);
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}
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/*
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* fls: find last (most-significant) bit set.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*
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* On powerpc, __ilog2(0) returns -1, but this is not safe in general
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*/
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static __inline__ int fls(unsigned int x)
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{
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return __ilog2(x) + 1;
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}
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/**
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* fls64 - find last set bit in a 64-bit word
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* @x: the word to search
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*
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* This is defined in a similar way as the libc and compiler builtin
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* ffsll, but returns the position of the most significant set bit.
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*
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* fls64(value) returns 0 if value is 0 or the position of the last
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* set bit if value is nonzero. The last (most significant) bit is
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* at position 64.
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*/
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#if BITS_PER_LONG == 32
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static inline int fls64(__u64 x)
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{
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__u32 h = x >> 32;
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if (h)
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return fls(h) + 32;
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return fls(x);
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}
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#elif BITS_PER_LONG == 64
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static inline int fls64(__u64 x)
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{
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if (x == 0)
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return 0;
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return __ilog2(x) + 1;
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}
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#else
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#error BITS_PER_LONG not 32 or 64
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#endif
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static inline int __ilog2_u64(u64 n)
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{
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return fls64(n) - 1;
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}
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static inline int ffs64(u64 x)
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{
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return __ilog2_u64(x & -x) + 1ull;
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}
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#ifdef __KERNEL__
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/*
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* ffs: find first bit set. 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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extern __inline__ int ffs(int x)
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{
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return __ilog2(x & -x) + 1;
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}
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/*
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* hweightN: returns the hamming weight (i.e. the number
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* of bits set) of a N-bit word
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*/
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#define hweight32(x) generic_hweight32(x)
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#define hweight16(x) generic_hweight16(x)
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#define hweight8(x) generic_hweight8(x)
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#endif /* __KERNEL__ */
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/*
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* This implementation of find_{first,next}_zero_bit was stolen from
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* Linus' asm-alpha/bitops.h.
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*/
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#define find_first_zero_bit(addr, size) \
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find_next_zero_bit((addr), (size), 0)
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extern __inline__ unsigned long find_next_zero_bit(void * addr,
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unsigned long size, unsigned long offset)
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{
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unsigned int * p = ((unsigned int *) addr) + (offset >> 5);
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unsigned int result = offset & ~31UL;
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unsigned int tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 31UL;
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if (offset) {
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tmp = *p++;
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tmp |= ~0UL >> (32-offset);
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if (size < 32)
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goto found_first;
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if (tmp != ~0U)
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goto found_middle;
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size -= 32;
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result += 32;
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}
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while (size >= 32) {
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if ((tmp = *p++) != ~0U)
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goto found_middle;
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result += 32;
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size -= 32;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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found_middle:
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return result + ffz(tmp);
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}
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#define _EXT2_HAVE_ASM_BITOPS_
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#ifdef __KERNEL__
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/*
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* test_and_{set,clear}_bit guarantee atomicity without
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* disabling interrupts.
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*/
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#define ext2_set_bit(nr, addr) test_and_set_bit((nr) ^ 0x18, addr)
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#define ext2_clear_bit(nr, addr) test_and_clear_bit((nr) ^ 0x18, addr)
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#else
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extern __inline__ int ext2_set_bit(int nr, void * addr)
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{
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int mask;
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unsigned char *ADDR = (unsigned char *) addr;
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int oldbit;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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oldbit = (*ADDR & mask) ? 1 : 0;
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*ADDR |= mask;
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return oldbit;
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}
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extern __inline__ int ext2_clear_bit(int nr, void * addr)
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{
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int mask;
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unsigned char *ADDR = (unsigned char *) addr;
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int oldbit;
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ADDR += nr >> 3;
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mask = 1 << (nr & 0x07);
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oldbit = (*ADDR & mask) ? 1 : 0;
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*ADDR = *ADDR & ~mask;
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return oldbit;
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}
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#endif /* __KERNEL__ */
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extern __inline__ int ext2_test_bit(int nr, __const__ void * addr)
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{
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__const__ unsigned char *ADDR = (__const__ unsigned char *) addr;
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return (ADDR[nr >> 3] >> (nr & 7)) & 1;
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}
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/*
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* This implementation of ext2_find_{first,next}_zero_bit was stolen from
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* Linus' asm-alpha/bitops.h and modified for a big-endian machine.
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*/
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#define ext2_find_first_zero_bit(addr, size) \
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ext2_find_next_zero_bit((addr), (size), 0)
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static __inline__ unsigned long ext2_find_next_zero_bit(void *addr,
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unsigned long size, unsigned long offset)
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{
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unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
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unsigned int result = offset & ~31UL;
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unsigned int tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= 31UL;
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if (offset) {
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tmp = cpu_to_le32p(p++);
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tmp |= ~0UL >> (32-offset);
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if (size < 32)
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goto found_first;
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if (tmp != ~0U)
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goto found_middle;
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size -= 32;
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result += 32;
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}
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while (size >= 32) {
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if ((tmp = cpu_to_le32p(p++)) != ~0U)
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goto found_middle;
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result += 32;
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size -= 32;
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}
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if (!size)
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return result;
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tmp = cpu_to_le32p(p);
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found_first:
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tmp |= ~0U << size;
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found_middle:
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return result + ffz(tmp);
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}
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/* Bitmap functions for the minix filesystem. */
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#define minix_test_and_set_bit(nr,addr) ext2_set_bit(nr,addr)
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#define minix_set_bit(nr,addr) ((void)ext2_set_bit(nr,addr))
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#define minix_test_and_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
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#define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
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#define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)
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#endif /* _PPC_BITOPS_H */
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