Merge tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.git] / arch / s390 / lib / find.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MSB0 numbered special bitops handling.
4  *
5  * The bits are numbered:
6  *   |0..............63|64............127|128...........191|192...........255|
7  *
8  * The reason for this bit numbering is the fact that the hardware sets bits
9  * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap
10  * from the 'wrong end'.
11  */
12
13 #include <linux/compiler.h>
14 #include <linux/bitops.h>
15 #include <linux/export.h>
16
17 unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size)
18 {
19         const unsigned long *p = addr;
20         unsigned long result = 0;
21         unsigned long tmp;
22
23         while (size & ~(BITS_PER_LONG - 1)) {
24                 if ((tmp = *(p++)))
25                         goto found;
26                 result += BITS_PER_LONG;
27                 size -= BITS_PER_LONG;
28         }
29         if (!size)
30                 return result;
31         tmp = (*p) & (~0UL << (BITS_PER_LONG - size));
32         if (!tmp)               /* Are any bits set? */
33                 return result + size;   /* Nope. */
34 found:
35         return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
36 }
37 EXPORT_SYMBOL(find_first_bit_inv);
38
39 unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
40                                 unsigned long offset)
41 {
42         const unsigned long *p = addr + (offset / BITS_PER_LONG);
43         unsigned long result = offset & ~(BITS_PER_LONG - 1);
44         unsigned long tmp;
45
46         if (offset >= size)
47                 return size;
48         size -= result;
49         offset %= BITS_PER_LONG;
50         if (offset) {
51                 tmp = *(p++);
52                 tmp &= (~0UL >> offset);
53                 if (size < BITS_PER_LONG)
54                         goto found_first;
55                 if (tmp)
56                         goto found_middle;
57                 size -= BITS_PER_LONG;
58                 result += BITS_PER_LONG;
59         }
60         while (size & ~(BITS_PER_LONG-1)) {
61                 if ((tmp = *(p++)))
62                         goto found_middle;
63                 result += BITS_PER_LONG;
64                 size -= BITS_PER_LONG;
65         }
66         if (!size)
67                 return result;
68         tmp = *p;
69 found_first:
70         tmp &= (~0UL << (BITS_PER_LONG - size));
71         if (!tmp)               /* Are any bits set? */
72                 return result + size;   /* Nope. */
73 found_middle:
74         return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
75 }
76 EXPORT_SYMBOL(find_next_bit_inv);