diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sparc64/lib/find_bit.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/sparc64/lib/find_bit.c')
-rw-r--r-- | arch/sparc64/lib/find_bit.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/arch/sparc64/lib/find_bit.c b/arch/sparc64/lib/find_bit.c new file mode 100644 index 00000000000..6059557067b --- /dev/null +++ b/arch/sparc64/lib/find_bit.c @@ -0,0 +1,127 @@ +#include <linux/bitops.h> + +/** + * find_next_bit - find the next set bit in a memory region + * @addr: The address to base the search on + * @offset: The bitnumber to start searching at + * @size: The maximum size to search + */ +unsigned long find_next_bit(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + const unsigned long *p = 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 << 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 >> (64 - size)); + if (tmp == 0UL) /* Are any bits set? */ + return result + size; /* Nope. */ +found_middle: + return result + __ffs(tmp); +} + +/* find_next_zero_bit() finds the first zero bit in a bit string of length + * 'size' bits, starting the search at bit 'offset'. This is largely based + * on Linus's ALPHA routines, which are pretty portable BTW. + */ + +unsigned long find_next_zero_bit(const unsigned long *addr, + unsigned long size, unsigned long offset) +{ + const unsigned long *p = 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; + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. */ +found_middle: + return result + ffz(tmp); +} + +unsigned long find_next_zero_le_bit(unsigned long *addr, unsigned long size, unsigned long offset) +{ + unsigned long *p = addr + (offset >> 6); + unsigned long result = offset & ~63UL; + unsigned long tmp; + + if (offset >= size) + return size; + size -= result; + offset &= 63UL; + if(offset) { + tmp = __swab64p(p++); + tmp |= (~0UL >> (64-offset)); + if(size < 64) + goto found_first; + if(~tmp) + goto found_middle; + size -= 64; + result += 64; + } + while(size & ~63) { + if(~(tmp = __swab64p(p++))) + goto found_middle; + result += 64; + size -= 64; + } + if(!size) + return result; + tmp = __swab64p(p); +found_first: + tmp |= (~0UL << size); + if (tmp == ~0UL) /* Are any bits zero? */ + return result + size; /* Nope. */ +found_middle: + return result + ffz(tmp); +} |