2 * MSB0 numbered special bitops handling.
4 * On s390x the bits are numbered:
5 * |0..............63|64............127|128...........191|192...........255|
7 * |0.....31|32....63|64....95|96...127|128..159|160..191|192..223|224..255|
9 * The reason for this bit numbering is the fact that the hardware sets bits
10 * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap
11 * from the 'wrong end'.
14 #include <linux/compiler.h>
15 #include <linux/bitops.h>
16 #include <linux/export.h>
18 unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size)
20 const unsigned long *p = addr;
21 unsigned long result = 0;
24 while (size & ~(BITS_PER_LONG - 1)) {
27 result += BITS_PER_LONG;
28 size -= BITS_PER_LONG;
32 tmp = (*p) & (~0UL << (BITS_PER_LONG - size));
33 if (!tmp) /* Are any bits set? */
34 return result + size; /* Nope. */
36 return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
38 EXPORT_SYMBOL(find_first_bit_inv);
40 unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size,
43 const unsigned long *p = addr + (offset / BITS_PER_LONG);
44 unsigned long result = offset & ~(BITS_PER_LONG - 1);
50 offset %= BITS_PER_LONG;
53 tmp &= (~0UL >> offset);
54 if (size < BITS_PER_LONG)
58 size -= BITS_PER_LONG;
59 result += BITS_PER_LONG;
61 while (size & ~(BITS_PER_LONG-1)) {
64 result += BITS_PER_LONG;
65 size -= BITS_PER_LONG;
71 tmp &= (~0UL << (BITS_PER_LONG - size));
72 if (!tmp) /* Are any bits set? */
73 return result + size; /* Nope. */
75 return result + (__fls(tmp) ^ (BITS_PER_LONG - 1));
77 EXPORT_SYMBOL(find_next_bit_inv);