Linux kernel mirror (for testing)
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linux
1/*
2 * include/asm-xtensa/bitops.h
3 *
4 * Atomic operations that C can't guarantee us.Useful for resource counting etc.
5 *
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
8 * for more details.
9 *
10 * Copyright (C) 2001 - 2005 Tensilica Inc.
11 */
12
13#ifndef _XTENSA_BITOPS_H
14#define _XTENSA_BITOPS_H
15
16#ifdef __KERNEL__
17
18#include <asm/processor.h>
19#include <asm/byteorder.h>
20#include <asm/system.h>
21
22#ifdef CONFIG_SMP
23# error SMP not supported on this architecture
24#endif
25
26#define smp_mb__before_clear_bit() barrier()
27#define smp_mb__after_clear_bit() barrier()
28
29#include <asm-generic/bitops/atomic.h>
30#include <asm-generic/bitops/non-atomic.h>
31
32#if XCHAL_HAVE_NSA
33
34static __inline__ int __cntlz (unsigned long x)
35{
36 int lz;
37 asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
38 return 31 - lz;
39}
40
41#else
42
43static __inline__ int __cntlz (unsigned long x)
44{
45 unsigned long sum, x1, x2, x4, x8, x16;
46 x1 = x & 0xAAAAAAAA;
47 x2 = x & 0xCCCCCCCC;
48 x4 = x & 0xF0F0F0F0;
49 x8 = x & 0xFF00FF00;
50 x16 = x & 0xFFFF0000;
51 sum = x2 ? 2 : 0;
52 sum += (x16 != 0) * 16;
53 sum += (x8 != 0) * 8;
54 sum += (x4 != 0) * 4;
55 sum += (x1 != 0);
56
57 return sum;
58}
59
60#endif
61
62/*
63 * ffz: Find first zero in word. Undefined if no zero exists.
64 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
65 */
66
67static __inline__ int ffz(unsigned long x)
68{
69 if ((x = ~x) == 0)
70 return 32;
71 return __cntlz(x & -x);
72}
73
74/*
75 * __ffs: Find first bit set in word. Return 0 for bit 0
76 */
77
78static __inline__ int __ffs(unsigned long x)
79{
80 return __cntlz(x & -x);
81}
82
83/*
84 * ffs: Find first bit set in word. This is defined the same way as
85 * the libc and compiler builtin ffs routines, therefore
86 * differs in spirit from the above ffz (man ffs).
87 */
88
89static __inline__ int ffs(unsigned long x)
90{
91 return __cntlz(x & -x) + 1;
92}
93
94/*
95 * fls: Find last (most-significant) bit set in word.
96 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
97 */
98
99static __inline__ int fls (unsigned int x)
100{
101 return __cntlz(x);
102}
103#include <asm-generic/bitops/fls64.h>
104#include <asm-generic/bitops/find.h>
105#include <asm-generic/bitops/ext2-non-atomic.h>
106
107#ifdef __XTENSA_EL__
108# define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr),(addr))
109# define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr),(addr))
110#elif defined(__XTENSA_EB__)
111# define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr) ^ 0x18, (addr))
112# define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr)^0x18,(addr))
113#else
114# error processor byte order undefined!
115#endif
116
117#include <asm-generic/bitops/hweight.h>
118#include <asm-generic/bitops/sched.h>
119#include <asm-generic/bitops/minix.h>
120
121#endif /* __KERNEL__ */
122
123#endif /* _XTENSA_BITOPS_H */