[patch 09/44] generic fls()

[Akinobu Mita <mita@miraclelinux.com>]

This patch introduces the C-language equivalent of the function:
int fls(int x);

In include/asm-generic/bitops/fls.h

This code largely copied from:
include/linux/bitops.h

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
 include/asm-generic/bitops/fls.h |   41 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 41 insertions(+)

Index: 2.6-git/include/asm-generic/bitops/fls.h
===================================================================
--- /dev/null
+++ 2.6-git/include/asm-generic/bitops/fls.h
@@ -0,0 +1,41 @@
+#ifndef _ASM_GENERIC_BITOPS_FLS_H_
+#define _ASM_GENERIC_BITOPS_FLS_H_
+
+/**
+ * fls - find last (most-significant) bit set
+ * @x: the word to search
+ *
+ * This is defined the same way as ffs.
+ * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
+ */
+
+static __inline__ int fls(int x)
+{
+       int r = 32;
+
+       if (!x)
+               return 0;
+       if (!(x & 0xffff0000u)) {
+               x <<= 16;
+               r -= 16;
+       }
+       if (!(x & 0xff000000u)) {
+               x <<= 8;
+               r -= 8;
+       }
+       if (!(x & 0xf0000000u)) {
+               x <<= 4;
+               r -= 4;
+       }
+       if (!(x & 0xc0000000u)) {
+               x <<= 2;
+               r -= 2;
+       }
+       if (!(x & 0x80000000u)) {
+               x <<= 1;
+               r -= 1;
+       }
+       return r;
+}
+
+#endif /* _ASM_GENERIC_BITOPS_FLS_H_ */

--