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Commit a8ad27d0 authored by David Howells's avatar David Howells Committed by Linus Torvalds
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[PATCH] FRV: Implement fls64()



Implement fls64() for FRV without recource to conditional jumps.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 92fc7072
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+41 −1
Original line number Diff line number Diff line
@@ -186,7 +186,47 @@ static inline int __test_bit(int nr, const volatile void * addr)
	bit;						\
})

#include <asm-generic/bitops/fls64.h>
/**
 * fls64 - find last bit set in a 64-bit value
 * @n: the value to search
 *
 * This is defined the same way as ffs:
 * - return 64..1 to indicate bit 63..0 most significant bit set
 * - return 0 to indicate no bits set
 */
static inline __attribute__((const))
int fls64(u64 n)
{
	union {
		u64 ll;
		struct { u32 h, l; };
	} _;
	int bit, x, y;

	_.ll = n;

	asm("	subcc.p		%3,gr0,gr0,icc0		\n"
	    "	subcc		%4,gr0,gr0,icc1		\n"
	    "	ckne		icc0,cc4		\n"
	    "	ckne		icc1,cc5		\n"
	    "	norcr		cc4,cc5,cc6		\n"
	    "	csub.p		%0,%0,%0	,cc6,1	\n"
	    "	orcr		cc5,cc4,cc4		\n"
	    "	andcr		cc4,cc5,cc4		\n"
	    "	cscan.p		%3,gr0,%0	,cc4,0	\n"
	    "   setlos		#64,%1			\n"
	    "	cscan.p		%4,gr0,%0	,cc4,1	\n"
	    "   setlos		#32,%2			\n"
	    "	csub.p		%1,%0,%0	,cc4,0	\n"
	    "	csub		%2,%0,%0	,cc4,1	\n"
	    : "=&r"(bit), "=r"(x), "=r"(y)
	    : "0r"(_.h), "r"(_.l)
	    : "icc0", "icc1", "cc4", "cc5", "cc6"
	    );
	return bit;

}

#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/hweight.h>