Re: [U-Boot-Users] [PATCH] ppc: Add u64 versions of fls64 and __ilog bitops

In message Pine.LNX.4.64.0806101618470.3027@blarg.am.freescale.net you wrote:

Signed-off-by: Kumar Gala galak@kernel.crashing.org

Comments and code do not match; you'r actually adding much more code.

+/*

• • fls: find last (most-significant) bit set.
• • Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
• */

+static __inline__ int fls(unsigned int x)

This is not a u64 version of fls64, or is it? ;-)

+static __inline__ unsigned long __fls(unsigned long x)

Neither is this...

Also: is fls() vs. __fls() a good way to differentiate between int and ulong?

• • fls64(value) returns 0 if value is 0 or the position of the last
• • set bit if value is nonzero. The last (most significant) bit is

Sorry, I can't parse this.

+#elif BITS_PER_LONG == 64 +static inline int fls64(__u64 x) +{

• if (x == 0)

• return 0;
  

• return __fls(x) + 1;

Do I have to understand where the "+1" is coming from?

+static inline int ffs64(u64 x) +{

• return __ilog2_u64(x & -x) + 1ull;

Isn't there an easier way to do this?

Best regards,

Wolfgang Denk