Define ffs/fls for all architectures

UBIFS requires fls(), which is not defined for arm (and some other
architectures) and this patch adds it. The implementation is taken from
Linux and is generic. ffs() is also defined for those that miss it.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>

7 files changed, 53 insertions, 0 deletions

diff --git a/include/asm-i386/bitops.h b/include/asm-i386/bitops.h
index b768e20fbb..ac6285aa5f 100644
--- a/include/asm-i386/bitops.h
+++ b/include/asm-i386/bitops.h
@@ -349,6 +349,7 @@ static __inline__ int ffs(int x)
 		"1:" : "=r" (r) : "g" (x));
 	return r+1;
 }
+#define ffs
 
 /**
  * hweightN - returns the hamming weight of a N-bit word
diff --git a/include/asm-m68k/bitops.h b/include/asm-m68k/bitops.h
index 0f9e8abe9c..e0c35fa7b0 100644
--- a/include/asm-m68k/bitops.h
+++ b/include/asm-m68k/bitops.h
@@ -51,6 +51,7 @@ extern __inline__ int ffs(int x)
 	return r;
 }
 #define __ffs(x) (ffs(x) - 1)
+#define ffs
 
 #endif /* __KERNEL__ */
 
diff --git a/include/asm-nios/bitops.h b/include/asm-nios/bitops.h
index 7744212b45..8315fb7caa 100644
--- a/include/asm-nios/bitops.h
+++ b/include/asm-nios/bitops.h
@@ -33,5 +33,6 @@ extern int test_and_set_bit(int nr, volatile void * a);
 extern int test_and_change_bit(int nr, volatile void * addr);
 extern int test_bit(int nr, volatile void * a);
 extern int ffs(int i);
+#define ffs
 
 #endif /* _ASM_NIOS_BITOPS_H */
diff --git a/include/asm-nios2/bitops.h b/include/asm-nios2/bitops.h
index e6c1a850d1..b01a89d63c 100644
--- a/include/asm-nios2/bitops.h
+++ b/include/asm-nios2/bitops.h
@@ -33,5 +33,6 @@ extern int test_and_set_bit(int nr, volatile void * a);
 extern int test_and_change_bit(int nr, volatile void * addr);
 extern int test_bit(int nr, volatile void * a);
 extern int ffs(int i);
+#define ffs
 
 #endif /* __ASM_NIOS2_BITOPS_H */
diff --git a/include/asm-ppc/bitops.h b/include/asm-ppc/bitops.h
index daa66cf918..9ed2f5d6fa 100644
--- a/include/asm-ppc/bitops.h
+++ b/include/asm-ppc/bitops.h
@@ -178,6 +178,7 @@ static __inline__ int fls(unsigned int x)
 {
 	return __ilog2(x) + 1;
 }
+#define fls
 
 /**
  * fls64 - find last set bit in a 64-bit word
@@ -230,6 +231,7 @@ extern __inline__ int ffs(int x)
 {
 	return __ilog2(x & -x) + 1;
 }
+#define ffs
 
 /*
  * hweightN: returns the hamming weight (i.e. the number
diff --git a/include/asm-sh/bitops.h b/include/asm-sh/bitops.h
index 410fba46ef..95167bd45a 100644
--- a/include/asm-sh/bitops.h
+++ b/include/asm-sh/bitops.h
@@ -146,6 +146,8 @@ static inline int ffs (int x)
 	}
 	return r;
 }
+#define ffs
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASM_SH_BITOPS_H */
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 387a81813b..e14e6c7b14 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -38,6 +38,43 @@ static inline int generic_ffs(int x)
 	return r;
 }
 
+/**
+ * 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 generic_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;
+}
+
+
 /*
  * hweightN: returns the hamming weight (i.e. the number
  * of bits set) of a N-bit word
@@ -82,6 +119,14 @@ static inline unsigned int generic_hweight8(unsigned int w)
 # define __clear_bit generic_clear_bit
 #endif
 
+#ifndef ffs
+# define ffs generic_ffs
+#endif
+
+#ifndef fls
+# define fls generic_fls
+#endif
+
 /**
  * __set_bit - Set a bit in memory
  * @nr: the bit to set