[U-Boot] [PATCH v4 3/4]: Define ffs/fls for all architectures

Simon Kagstrom
2009-08-24T07:10:12Z

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>
---
ChangeLog:
v2: Unify code style (empty line between ffs/fls)
v3: Move the definition to generic code (Mike Frysinger)

include/asm-i386/bitops.h | 1 +
include/asm-m68k/bitops.h | 1 +
include/asm-nios/bitops.h | 1 +
include/asm-nios2/bitops.h | 1 +
include/asm-ppc/bitops.h | 2 +
include/asm-sh/bitops.h | 2 +
include/linux/bitops.h | 45 ++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/include/asm-i386/bitops.h b/include/asm-i386/bitops.h
index b768e20..ac6285a 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 0f9e8ab..e0c35fa 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 7744212..8315fb7 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 e6c1a85..b01a89d 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 daa66cf..9ed2f5d 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 410fba4..95167bd 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 387a818..e14e6c7 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
--
1.6.0.4