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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /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.c127
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);
+}