case HALF_EVEN:
        // Since sqrt(2) is irrational, log2(x) - logFloor cannot be exactly 0.5
        int leadingZeros = Long.numberOfLeadingZeros(x);
        long cmp = MAX_POWER_OF_SQRT2_UNSIGNED >>> leadingZeros;
        // floor(2^(logFloor + 0.5))
        int logFloor = (Long.SIZE - 1) - leadingZeros;
        return logFloor + lessThanBranchFree(cmp, x);
    }
    throw new AssertionError("impossible");
  }

pkg math/bits (openbsd-amd64-cgo), const UintSize = 64
pkg math/bits (windows-386), const UintSize = 32
pkg math/bits (windows-amd64), const UintSize = 64
pkg math/bits, const UintSize ideal-int
pkg math/bits, func LeadingZeros(uint) int
pkg math/bits, func LeadingZeros16(uint16) int
pkg math/bits, func LeadingZeros32(uint32) int
pkg math/bits, func LeadingZeros64(uint64) int
pkg math/bits, func LeadingZeros8(uint8) int