Re: [Qemu-devel] [PATCH v2] utils: Add pow2ceil()

[Richard Henderson]

On 02/25/2015 02:45 AM, Markus Armbruster wrote:
> return 0x8000000000000000u >> (clz64(value - 1) - 1);

I realize this was weeks ago, but it would certainly be preferable to shift a
small constant left than a large constant right.

Most RISC machines can't form 0x8000000000000000ull without loading 1 and then
left shifting to start with.  So end the end you're better off with

  return 1ull << (63 - clz64(value));


r~