82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
#ifndef _ASM_GENERIC_BITOPS_H_
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#define _ASM_GENERIC_BITOPS_H_
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/*
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* For the benefit of those who are trying to port Linux to another
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* architecture, here are some C-language equivalents. You should
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* recode these in the native assembly language, if at all possible.
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* To guarantee atomicity, these routines call cli() and sti() to
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* disable interrupts while they operate. (You have to provide inline
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* routines to cli() and sti().)
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*
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* Also note, these routines assume that you have 32 bit longs.
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* You will have to change this if you are trying to port Linux to the
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* Alpha architecture or to a Cray. :-)
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*
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* C language equivalents written by Theodore Ts'o, 9/26/92
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*/
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extern __inline__ int set_bit(int nr,long * addr)
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{
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int mask, retval;
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addr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cli();
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retval = (mask & *addr) != 0;
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*addr |= mask;
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sti();
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return retval;
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}
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extern __inline__ int clear_bit(int nr, long * addr)
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{
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int mask, retval;
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addr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cli();
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retval = (mask & *addr) != 0;
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*addr &= ~mask;
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sti();
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return retval;
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}
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extern __inline__ int test_bit(int nr, const unsigned long * addr)
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{
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int mask;
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addr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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return ((mask & *addr) != 0);
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}
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/*
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* fls: find last bit set.
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*/
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#define fls(x) generic_fls(x)
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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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#define ffs(x) generic_ffs(x)
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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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#endif /* _ASM_GENERIC_BITOPS_H */
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