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Commit ef55d53c authored by David Howells's avatar David Howells Committed by Linus Torvalds
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[PATCH] LOG2: Provide ilog2() fallbacks for powerpc 



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

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 39d61db0

arch/powerpc/Kconfig

+2 −2
Original line number Diff line number Diff line
@@ -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

include/asm-powerpc/bitops.h

+20 −1
Original line number Diff line number Diff line
@@ -190,7 +190,8 @@ static __inline__ void set_bits(unsigned long mask, unsigned long *addr) 
 * 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 long x) 
	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

include/asm-powerpc/page_32.h

+1 −9
Original line number Diff line number Diff line
@@ -26,15 +26,7 @@ extern void clear_pages(void *page, int order); 
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__ */