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#ifndef _ASM_GENERIC_BITOPS_H_ #define _ASM_GENERIC_BITOPS_H_ /* * For the benefit of those who are trying to port Linux to another * architecture, here are some C-language equivalents. You should * recode these in the native assembly language, if at all possible. * To guarantee atomicity, these routines call cli() and sti() to * disable interrupts while they operate. (You have to provide inline * routines to cli() and sti().) * * Also note, these routines assume that you have 32 bit integers. * You will have to change this if you are trying to port Linux to the * Alpha architecture or to a Cray. :-) * * C language equivalents written by Theodore Ts'o, 9/26/92 */ extern __inline__ int set_bit(int nr,int * addr) { int mask, retval; addr += nr >> 5; mask = 1 << (nr & 0x1f); cli(); retval = (mask & *addr) != 0; *addr |= mask; sti(); return retval; } extern __inline__ int clear_bit(int nr, int * addr) { int mask, retval; addr += nr >> 5; mask = 1 << (nr & 0x1f); cli(); retval = (mask & *addr) != 0; *addr &= ~mask; sti(); return retval; } extern __inline__ int test_bit(int nr, int * addr) { int mask; addr += nr >> 5; mask = 1 << (nr & 0x1f); return ((mask & *addr) != 0); } #ifdef __KERNEL__ /* * ffs: find first bit set. This is defined the same way as * the libc and compiler builtin ffs routines, therefore * differs in spirit from the above ffz (man ffs). */ #define ffs(x) generic_ffs(x) /* * hweightN: returns the hamming weight (i.e. the number * of bits set) of a N-bit word */ #define hweight32(x) generic_hweight32(x) #define hweight16(x) generic_hweight16(x) #define hweight8(x) generic_hweight8(x) #endif /* __KERNEL__ */ #endif /* _ASM_GENERIC_BITOPS_H */ |