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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 /lib/find_next_bit.c
downloadlinux-2.6.38-lt-ux500-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-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 'lib/find_next_bit.c')
-rw-r--r--lib/find_next_bit.c55
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
new file mode 100644
index 00000000000..d08302d2a42
--- /dev/null
+++ b/lib/find_next_bit.c
@@ -0,0 +1,55 @@
+/* find_next_bit.c: fallback find next bit implementation
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/bitops.h>
+
+int find_next_bit(const unsigned long *addr, int size, int offset)
+{
+ const unsigned long *base;
+ const int NBITS = sizeof(*addr) * 8;
+ unsigned long tmp;
+
+ base = addr;
+ if (offset) {
+ int suboffset;
+
+ addr += offset / NBITS;
+
+ suboffset = offset % NBITS;
+ if (suboffset) {
+ tmp = *addr;
+ tmp >>= suboffset;
+ if (tmp)
+ goto finish;
+ }
+
+ addr++;
+ }
+
+ while ((tmp = *addr) == 0)
+ addr++;
+
+ offset = (addr - base) * NBITS;
+
+ finish:
+ /* count the remaining bits without using __ffs() since that takes a 32-bit arg */
+ while (!(tmp & 0xff)) {
+ offset += 8;
+ tmp >>= 8;
+ }
+
+ while (!(tmp & 1)) {
+ offset++;
+ tmp >>= 1;
+ }
+
+ return offset;
+}