From: Alexander van Heukelum <heukelum@mailshack.com>
To: Andrew Morton <akpm@linux-foundation.org>,
linux-arch <linux-arch@vger.kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Andi Kleen <andi@firstfloor.org>,
LKML <linux-kernel@vger.kernel.org>,
heukelum@fastmail.fm
Subject: [2/3] Implement __fls on all 64-bit archs
Date: Sat, 15 Mar 2008 18:31:49 +0100 [thread overview]
Message-ID: <20080315173149.GB21659@mailshack.com> (raw)
In-Reply-To: <20080315172913.GA21648@mailshack.com>
Implement __fls on all 64-bit archs:
alpha has an implementation of fls64.
Added __fls(x) = fls64(x) - 1.
ia64 has fls, but not __fls.
Added __fls based on code of fls.
mips and powerpc have __ilog2, which is the same as __fls.
Added __fls = __ilog2.
parisc, s390, sh and sparc64:
Include generic __fls.
x86_64 already has __fls.
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
---
include/asm-alpha/bitops.h | 5 +++++
include/asm-ia64/bitops.h | 16 ++++++++++++++++
include/asm-mips/bitops.h | 5 +++++
include/asm-parisc/bitops.h | 1 +
include/asm-powerpc/bitops.h | 5 +++++
include/asm-s390/bitops.h | 1 +
include/asm-sh/bitops.h | 1 +
include/asm-sparc64/bitops.h | 1 +
8 files changed, 35 insertions(+), 0 deletions(-)
diff --git a/include/asm-alpha/bitops.h b/include/asm-alpha/bitops.h
index 9e19a70..15f3ae2 100644
--- a/include/asm-alpha/bitops.h
+++ b/include/asm-alpha/bitops.h
@@ -388,6 +388,11 @@ static inline int fls64(unsigned long x)
}
#endif
+static inline unsigned long __fls(unsigned long x)
+{
+ return fls64(x) - 1;
+}
+
static inline int fls(int x)
{
return fls64((unsigned int) x);
diff --git a/include/asm-ia64/bitops.h b/include/asm-ia64/bitops.h
index 953d3df..e2ca800 100644
--- a/include/asm-ia64/bitops.h
+++ b/include/asm-ia64/bitops.h
@@ -407,6 +407,22 @@ fls (int t)
return ia64_popcnt(x);
}
+/*
+ * Find the last (most significant) bit set. Undefined for x==0.
+ * Bits are numbered from 0..63 (e.g., __fls(9) == 3).
+ */
+static inline unsigned long
+__fls (unsigned long x)
+{
+ x |= x >> 1;
+ x |= x >> 2;
+ x |= x >> 4;
+ x |= x >> 8;
+ x |= x >> 16;
+ x |= x >> 32;
+ return ia64_popcnt(x) - 1;
+}
+
#include <asm-generic/bitops/fls64.h>
/*
diff --git a/include/asm-mips/bitops.h b/include/asm-mips/bitops.h
index ec75ce4..c2bd126 100644
--- a/include/asm-mips/bitops.h
+++ b/include/asm-mips/bitops.h
@@ -591,6 +591,11 @@ static inline int __ilog2(unsigned long x)
return 63 - lz;
}
+static inline unsigned long __fls(unsigned long x)
+{
+ return __ilog2(x);
+}
+
#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
/*
diff --git a/include/asm-parisc/bitops.h b/include/asm-parisc/bitops.h
index f8eebcb..7a6ea10 100644
--- a/include/asm-parisc/bitops.h
+++ b/include/asm-parisc/bitops.h
@@ -210,6 +210,7 @@ static __inline__ int fls(int x)
return ret;
}
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>
diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h
index 220d9a7..2fc0c45 100644
--- a/include/asm-powerpc/bitops.h
+++ b/include/asm-powerpc/bitops.h
@@ -312,6 +312,11 @@ static __inline__ int fls(unsigned int x)
asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
return 32 - lz;
}
+
+static __inline__ unsigned long __fls(unsigned long x)
+{
+ return __ilog2(x);
+}
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/hweight.h>
diff --git a/include/asm-s390/bitops.h b/include/asm-s390/bitops.h
index 965394e..b4eb24a 100644
--- a/include/asm-s390/bitops.h
+++ b/include/asm-s390/bitops.h
@@ -769,6 +769,7 @@ static inline int sched_find_first_bit(unsigned long *b)
}
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#include <asm-generic/bitops/hweight.h>
diff --git a/include/asm-sh/bitops.h b/include/asm-sh/bitops.h
index b6ba5a6..d7d382f 100644
--- a/include/asm-sh/bitops.h
+++ b/include/asm-sh/bitops.h
@@ -95,6 +95,7 @@ static inline unsigned long ffz(unsigned long word)
#include <asm-generic/bitops/ext2-atomic.h>
#include <asm-generic/bitops/minix.h>
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#endif /* __KERNEL__ */
diff --git a/include/asm-sparc64/bitops.h b/include/asm-sparc64/bitops.h
index 982ce89..11f9d81 100644
--- a/include/asm-sparc64/bitops.h
+++ b/include/asm-sparc64/bitops.h
@@ -34,6 +34,7 @@ extern void change_bit(unsigned long nr, volatile unsigned long *addr);
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/__ffs.h>
#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
#include <asm-generic/bitops/fls64.h>
#ifdef __KERNEL__
next prev parent reply other threads:[~2008-03-15 17:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-15 17:29 [0/3] Improve generic fls64 for 64-bit machines Alexander van Heukelum
2008-03-15 17:30 ` [1/3] Introduce a generic __fls implementation Alexander van Heukelum
2008-03-15 17:31 ` Alexander van Heukelum [this message]
2008-03-15 17:32 ` [3/3] Use __fls for fls64 on 64-bit archs Alexander van Heukelum
2008-07-05 16:56 ` Ricardo M. Correia
2008-07-05 17:53 ` [PATCH] x86: fix description of __fls(): __fls(0) is undefined Alexander van Heukelum
2008-07-18 12:33 ` Ingo Molnar
2008-03-21 13:10 ` [0/3] Improve generic fls64 for 64-bit machines Ingo Molnar
2008-04-03 17:19 ` Benny Halevy
2008-04-04 14:22 ` Alexander van Heukelum
2008-04-06 15:03 ` Benny Halevy
2008-04-06 19:10 ` Alexander van Heukelum
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