[PATCH] v850: add find_next_bit

[Since many archs use the same implementation of find_next_bit, it might
be nice to have `generic_find_next_bit' or something.]

Signed-off-by: Miles Bader <miles@gnu.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 76 insertions, 0 deletions

diff --git a/include/asm-v850/bitops.h b/include/asm-v850/bitops.h
index c837ea08c611..5ca65390186b 100644
--- a/include/asm-v850/bitops.h
+++ b/include/asm-v850/bitops.h
@@ -193,10 +193,86 @@ extern __inline__ int find_next_zero_bit (void *addr, int size, int offset)
 	return result + ffz (tmp);
 }
 
+
+/* This is the same as generic_ffs, but we can't use that because it's
+   inline and the #include order mucks things up.  */
+static inline int generic_ffs_for_find_next_bit(int x)
+{
+	int r = 1;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xffff)) {
+		x >>= 16;
+		r += 16;
+	}
+	if (!(x & 0xff)) {
+		x >>= 8;
+		r += 8;
+	}
+	if (!(x & 0xf)) {
+		x >>= 4;
+		r += 4;
+	}
+	if (!(x & 3)) {
+		x >>= 2;
+		r += 2;
+	}
+	if (!(x & 1)) {
+		x >>= 1;
+		r += 1;
+	}
+	return r;
+}
+
+/*
+ * Find next one bit in a bitmap reasonably efficiently.
+ */
+static __inline__ unsigned long find_next_bit(const unsigned long *addr,
+	unsigned long size, unsigned long offset)
+{
+	unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
+	unsigned int result = offset & ~31UL;
+	unsigned int tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset &= 31UL;
+	if (offset) {
+		tmp = *p++;
+		tmp &= ~0UL << offset;
+		if (size < 32)
+			goto found_first;
+		if (tmp)
+			goto found_middle;
+		size -= 32;
+		result += 32;
+	}
+	while (size >= 32) {
+		if ((tmp = *p++) != 0)
+			goto found_middle;
+		result += 32;
+		size -= 32;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+
+found_first:
+	tmp &= ~0UL >> (32 - size);
+	if (tmp == 0UL)        /* Are any bits set? */
+		return result + size; /* Nope. */
+found_middle:
+	return result + generic_ffs_for_find_next_bit(tmp);
+}
+
+
 #define ffs(x) generic_ffs (x)
 #define fls(x) generic_fls (x)
 #define __ffs(x) ffs(x)
 
+
 /*
  * This is just `generic_ffs' from <linux/bitops.h>, except that it assumes
  * that at least one bit is set, and returns the real index of the bit