2 highbit - index of highest bit in binary representation of integer
13 If x is a nonzero integer, highbit(x) returns the index of the
14 highest bit in the binary representation of abs(x). Equivalently,
15 highbit(x) = n if 2^n <= abs(x) < 2^(n + 1); the binary
16 representation of x then has n + 1 digits.
19 > print highbit(2), highbit(3), highbit(4), highbit(-15), highbit(2^27)
26 LEN zhighbit(ZVALUE x);