2 * include/asm-xtensa/bitops.h
4 * Atomic operations that C can't guarantee us.Useful for resource counting etc.
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
10 * Copyright (C) 2001 - 2007 Tensilica Inc.
13 #ifndef _XTENSA_BITOPS_H
14 #define _XTENSA_BITOPS_H
18 #include <asm/processor.h>
19 #include <asm/byteorder.h>
20 #include <asm/system.h>
23 # error SMP not supported on this architecture
26 #define smp_mb__before_clear_bit() barrier()
27 #define smp_mb__after_clear_bit() barrier()
29 #include <asm-generic/bitops/atomic.h>
30 #include <asm-generic/bitops/non-atomic.h>
34 static inline unsigned long __cntlz (unsigned long x)
37 asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
42 * ffz: Find first zero in word. Undefined if no zero exists.
43 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
46 static inline int ffz(unsigned long x)
48 return 31 - __cntlz(~x & -~x);
52 * __ffs: Find first bit set in word. Return 0 for bit 0
55 static inline int __ffs(unsigned long x)
57 return 31 - __cntlz(x & -x);
64 * ffs: Find first bit set in word. This is defined the same way as
65 * the libc and compiler builtin ffs routines, therefore
66 * differs in spirit from the above ffz (man ffs).
69 static inline int ffs(unsigned long x)
71 return 32 - __cntlz(x & -x);
75 * fls: Find last (most-significant) bit set in word.
76 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
79 static inline int fls (unsigned int x)
81 return 32 - __cntlz(x);
86 /* Use the generic implementation if we don't have the nsa/nsau instructions. */
88 # include <asm-generic/bitops/ffs.h>
89 # include <asm-generic/bitops/__ffs.h>
90 # include <asm-generic/bitops/ffz.h>
91 # include <asm-generic/bitops/fls.h>
95 #include <asm-generic/bitops/fls64.h>
96 #include <asm-generic/bitops/find.h>
97 #include <asm-generic/bitops/ext2-non-atomic.h>
100 # define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr),(addr))
101 # define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr),(addr))
102 #elif defined(__XTENSA_EB__)
103 # define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr) ^ 0x18, (addr))
104 # define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr)^0x18,(addr))
106 # error processor byte order undefined!
109 #include <asm-generic/bitops/hweight.h>
110 #include <asm-generic/bitops/sched.h>
111 #include <asm-generic/bitops/minix.h>
113 #endif /* __KERNEL__ */
115 #endif /* _XTENSA_BITOPS_H */