X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Ffind_next_bit.c;fp=lib%2Ffind_next_bit.c;h=c05b4b19cf6cac90e407eac98e870130bbb3e66a;hb=64ba3f394c830ec48a1c31b53dcae312c56f1604;hp=bda0d71a25144c110df24920b6320470e9c213a8;hpb=be1e6109ac94a859551f8e1774eb9a8469fe055c;p=linux-2.6.git

diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index bda0d71a2..c05b4b19c 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -11,171 +11,48 @@
 
 #include <linux/bitops.h>
 #include <linux/module.h>
-#include <asm/types.h>
-#include <asm/byteorder.h>
 
-#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
-
-/**
- * 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)
+int find_next_bit(const unsigned long *addr, int size, int offset)
 {
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG-1);
+	const unsigned long *base;
+	const int NBITS = sizeof(*addr) * 8;
 	unsigned long tmp;
 
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset %= BITS_PER_LONG;
+	base = addr;
 	if (offset) {
-		tmp = *(p++);
-		tmp &= (~0UL << offset);
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
-	}
-	while (size & ~(BITS_PER_LONG-1)) {
-		if ((tmp = *(p++)))
-			goto found_middle;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
-	}
-	if (!size)
-		return result;
-	tmp = *p;
+		int suboffset;
 
-found_first:
-	tmp &= (~0UL >> (BITS_PER_LONG - size));
-	if (tmp == 0UL)		/* Are any bits set? */
-		return result + size;	/* Nope. */
-found_middle:
-	return result + __ffs(tmp);
-}
+		addr += offset / NBITS;
 
-EXPORT_SYMBOL(find_next_bit);
+		suboffset = offset % NBITS;
+		if (suboffset) {
+			tmp = *addr;
+			tmp >>= suboffset;
+			if (tmp)
+				goto finish;
+		}
 
-/*
- * This implementation of find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h.
- */
-unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
-		unsigned long offset)
-{
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG-1);
-	unsigned long tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset %= BITS_PER_LONG;
-	if (offset) {
-		tmp = *(p++);
-		tmp |= ~0UL >> (BITS_PER_LONG - offset);
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (~tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
-	}
-	while (size & ~(BITS_PER_LONG-1)) {
-		if (~(tmp = *(p++)))
-			goto found_middle;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
+		addr++;
 	}
-	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);
-}
-
-EXPORT_SYMBOL(find_next_zero_bit);
 
-#ifdef __BIG_ENDIAN
+	while ((tmp = *addr) == 0)
+		addr++;
 
-/* include/linux/byteorder does not support "unsigned long" type */
-static inline unsigned long ext2_swabp(const unsigned long * x)
-{
-#if BITS_PER_LONG == 64
-	return (unsigned long) __swab64p((u64 *) x);
-#elif BITS_PER_LONG == 32
-	return (unsigned long) __swab32p((u32 *) x);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
-
-/* include/linux/byteorder doesn't support "unsigned long" type */
-static inline unsigned long ext2_swab(const unsigned long y)
-{
-#if BITS_PER_LONG == 64
-	return (unsigned long) __swab64((u64) y);
-#elif BITS_PER_LONG == 32
-	return (unsigned long) __swab32((u32) y);
-#else
-#error BITS_PER_LONG not defined
-#endif
-}
+	offset = (addr - base) * NBITS;
 
-unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned
-		long size, unsigned long offset)
-{
-	const unsigned long *p = addr + BITOP_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG - 1);
-	unsigned long tmp;
-
-	if (offset >= size)
-		return size;
-	size -= result;
-	offset &= (BITS_PER_LONG - 1UL);
-	if (offset) {
-		tmp = ext2_swabp(p++);
-		tmp |= (~0UL >> (BITS_PER_LONG - offset));
-		if (size < BITS_PER_LONG)
-			goto found_first;
-		if (~tmp)
-			goto found_middle;
-		size -= BITS_PER_LONG;
-		result += BITS_PER_LONG;
+ finish:
+	/* count the remaining bits without using __ffs() since that takes a 32-bit arg */
+	while (!(tmp & 0xff)) {
+		offset += 8;
+		tmp >>= 8;
 	}
 
-	while (size & ~(BITS_PER_LONG - 1)) {
-		if (~(tmp = *(p++)))
-			goto found_middle_swap;
-		result += BITS_PER_LONG;
-		size -= BITS_PER_LONG;
+	while (!(tmp & 1)) {
+		offset++;
+		tmp >>= 1;
 	}
-	if (!size)
-		return result;
-	tmp = ext2_swabp(p);
-found_first:
-	tmp |= ~0UL << size;
-	if (tmp == ~0UL)	/* Are any bits zero? */
-		return result + size; /* Nope. Skip ffz */
-found_middle:
-	return result + ffz(tmp);
 
-found_middle_swap:
-	return result + ffz(ext2_swab(tmp));
+	return offset;
 }
 
-EXPORT_SYMBOL(generic_find_next_zero_le_bit);
-
-#endif /* __BIG_ENDIAN */
+EXPORT_SYMBOL(find_next_bit);