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author | Michal Marek <mmarek@suse.cz> | 2014-01-02 17:02:06 +0400 |
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committer | Michal Marek <mmarek@suse.cz> | 2014-01-02 17:02:06 +0400 |
commit | 37e2c2a775fc887acd1432908478dfd532f7f00f (patch) | |
tree | e51ebc699d8e262fd47e0913be6a711cb1a7b565 /arch/s390/lib/find.c | |
parent | 1c8ddae09f4c102b97c9086cc70347e89468a547 (diff) | |
parent | 6ce4eac1f600b34f2f7f58f9cd8f0503d79e42ae (diff) | |
download | linux-37e2c2a775fc887acd1432908478dfd532f7f00f.tar.xz |
Merge commit v3.13-rc1 into kbuild/misc
Diffstat (limited to 'arch/s390/lib/find.c')
-rw-r--r-- | arch/s390/lib/find.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/arch/s390/lib/find.c b/arch/s390/lib/find.c new file mode 100644 index 000000000000..620d34d6487e --- /dev/null +++ b/arch/s390/lib/find.c @@ -0,0 +1,77 @@ +/* + * MSB0 numbered special bitops handling. + * + * On s390x the bits are numbered: + * |0..............63|64............127|128...........191|192...........255| + * and on s390: + * |0.....31|31....63|64....95|96...127|128..159|160..191|192..223|224..255| + * + * The reason for this bit numbering is the fact that the hardware sets bits + * in a bitmap starting at bit 0 (MSB) and we don't want to scan the bitmap + * from the 'wrong end'. + */ + +#include <linux/compiler.h> +#include <linux/bitops.h> +#include <linux/export.h> + +unsigned long find_first_bit_inv(const unsigned long *addr, unsigned long size) +{ + const unsigned long *p = addr; + unsigned long result = 0; + unsigned long tmp; + + while (size & ~(BITS_PER_LONG - 1)) { + if ((tmp = *(p++))) + goto found; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = (*p) & (~0UL << (BITS_PER_LONG - size)); + if (!tmp) /* Are any bits set? */ + return result + size; /* Nope. */ +found: + return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); +} +EXPORT_SYMBOL(find_first_bit_inv); + +unsigned long find_next_bit_inv(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + const unsigned long *p = addr + (offset / BITS_PER_LONG); + unsigned long result = offset & ~(BITS_PER_LONG - 1); + unsigned long tmp; + + if (offset >= size) + return size; + size -= result; + offset %= BITS_PER_LONG; + if (offset) { + tmp = *(p++); + tmp &= (~0UL >> offset); + if (size < BITS_PER_LONG) + goto found_first; + if (tmp) + goto found_middle; + size -= BITS_PER_LONG; + result += BITS_PER_LONG; + } + while (size & ~(BITS_PER_LONG-1)) { + if ((tmp = *(p++))) + goto found_middle; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = *p; +found_first: + tmp &= (~0UL << (BITS_PER_LONG - size)); + if (!tmp) /* Are any bits set? */ + return result + size; /* Nope. */ +found_middle: + return result + (__fls(tmp) ^ (BITS_PER_LONG - 1)); +} +EXPORT_SYMBOL(find_next_bit_inv); |