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Subject[PATCH 4/4] LOG2: Provide ilog2() fallbacks for powerpc [try #4]
Date
From: David Howells <dhowells@redhat.com>

Provide ilog2() fallbacks for powerpc for 32-bit numbers and 64-bit numbers on
ppc64.

Signed-Off-By: David Howells <dhowells@redhat.com>
---
arch/powerpc/Kconfig | 4 ++--
include/asm-powerpc/bitops.h | 21 ++++++++++++++++++++-
include/asm-powerpc/page_32.h | 10 +---------
3 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1cf67b7..9515489 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -43,11 +43,11 @@ config RWSEM_XCHGADD_ALGORITHM

config ARCH_HAS_ILOG2_U32
bool
- default n
+ default y

config ARCH_HAS_ILOG2_U64
bool
- default n
+ default y if 64BIT

config GENERIC_HWEIGHT
bool
diff --git a/include/asm-powerpc/bitops.h b/include/asm-powerpc/bitops.h
index c341063..0288144 100644
--- a/include/asm-powerpc/bitops.h
+++ b/include/asm-powerpc/bitops.h
@@ -190,7 +190,8 @@ #include <asm-generic/bitops/non-atomic.
* Return the zero-based bit position (LE, not IBM bit numbering) of
* the most significant 1-bit in a double word.
*/
-static __inline__ int __ilog2(unsigned long x)
+static __inline__ __attribute__((const))
+int __ilog2(unsigned long x)
{
int lz;

@@ -198,6 +199,24 @@ static __inline__ int __ilog2(unsigned l
return BITS_PER_LONG - 1 - lz;
}

+static inline __attribute__((const))
+int __ilog2_u32(u32 n)
+{
+ int bit;
+ asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
+ return 31 - bit;
+}
+
+#ifdef __powerpc64__
+static inline __attribute__((const))
+int __ilog2_u64(u32 n)
+{
+ int bit;
+ asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
+ return 63 - bit;
+}
+#endif
+
/*
* Determines the bit position of the least significant 0 bit in the
* specified double word. The returned bit position will be
diff --git a/include/asm-powerpc/page_32.h b/include/asm-powerpc/page_32.h
index 2677bad..07f6d3c 100644
--- a/include/asm-powerpc/page_32.h
+++ b/include/asm-powerpc/page_32.h
@@ -26,15 +26,7 @@ extern void clear_pages(void *page, int
static inline void clear_page(void *page) { clear_pages(page, 0); }
extern void copy_page(void *to, void *from);

-/* Pure 2^n version of get_order */
-extern __inline__ int get_order(unsigned long size)
-{
- int lz;
-
- size = (size-1) >> PAGE_SHIFT;
- asm ("cntlzw %0,%1" : "=r" (lz) : "r" (size));
- return 32 - lz;
-}
+#include <asm-generic/page.h>

#endif /* __ASSEMBLY__ */

-
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