[PATCH] FRV: Implement fls64()

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

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 41 insertions, 1 deletions

diff --git a/include/asm-frv/bitops.h b/include/asm-frv/bitops.h
index 97fb746f76c7..591eecc1f8cd 100644
--- a/include/asm-frv/bitops.h
+++ b/include/asm-frv/bitops.h
@@ -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>