1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
#ifndef _ALPHA_BITOPS_H
#define _ALPHA_BITOPS_H
/*
* Copyright 1994, Linus Torvalds.
*/
/*
* These have to be done with inline assembly: that way the bit-setting
* is guaranteed to be atomic. All bit operations return 0 if the bit
* was cleared before the operation and != 0 if it was not.
*
* To get proper branch prediction for the main line, we must branch
* forward to code at the end of this object's .text section, then
* branch back to restart the operation.
*
* bit 0 is the LSB of addr; bit 64 is the LSB of (addr+1).
*/
extern __inline__ unsigned long set_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n"
" bne %2,2f\n"
" xor %0,%3,%0\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
"2:\n"
".text 2\n"
"3: br 1b\n"
".text"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long clear_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n\t"
" beq %2,2f\n\t"
" xor %0,%3,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
"2:\n"
".text 2\n"
"3: br 1b\n"
".text"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long change_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n\t"
" xor %0,%3,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
".text 2\n"
"3: br 1b\n"
".text"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long test_bit(int nr, const void * addr)
{
return 1UL & (((const int *) addr)[nr >> 5] >> (nr & 31));
}
/*
* ffz = Find First Zero in word. Undefined if no zero exists,
* so code should check against ~0UL first..
*
* Do a binary search on the bits. Due to the nature of large
* constants on the alpha, it is worthwhile to split the search.
*/
extern inline unsigned long ffz_b(unsigned long x)
{
unsigned long sum = 0;
x = ~x & -~x; /* set first 0 bit, clear others */
if (x & 0xF0) sum += 4;
if (x & 0xCC) sum += 2;
if (x & 0xAA) sum += 1;
return sum;
}
extern inline unsigned long ffz(unsigned long word)
{
unsigned long bits, qofs, bofs;
__asm__("cmpbge %1,%2,%0" : "=r"(bits) : "r"(word), "r"(~0UL));
qofs = ffz_b(bits);
__asm__("extbl %1,%2,%0" : "=r"(bits) : "r"(word), "r"(qofs));
bofs = ffz_b(bits);
return qofs*8 + bofs;
}
/*
* Find next zero bit in a bitmap reasonably efficiently..
*/
extern inline unsigned long find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
{
unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
unsigned long result = offset & ~63UL;
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= 63UL;
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (64-offset);
if (size < 64)
goto found_first;
if (~tmp)
goto found_middle;
size -= 64;
result += 64;
}
while (size & ~63UL) {
if (~(tmp = *(p++)))
goto found_middle;
result += 64;
size -= 64;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
/*
* The optimizer actually does good code for this case..
*/
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
#ifdef __KERNEL__
#define ext2_set_bit set_bit
#define ext2_clear_bit clear_bit
#define ext2_test_bit test_bit
#define ext2_find_first_zero_bit find_first_zero_bit
#define ext2_find_next_zero_bit find_next_zero_bit
/* Bitmap functions for the minix filesystem. */
#define minix_set_bit(nr,addr) set_bit(nr,addr)
#define minix_clear_bit(nr,addr) clear_bit(nr,addr)
#define minix_test_bit(nr,addr) test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
#endif /* __KERNEL__ */
#endif /* _ALPHA_BITOPS_H */
|
