Bit-fiddling:

Set the low-order b bits of x to 1; the others to 0. For example, if b is 3, x should be 7. Pay special attention to the edge cases: if b is 32 x should be 1; if b is 0 x should be 0. Do not use - in your solution.

Provided input(s): b

Permitted: 40 operations (may use !, ~, +, <<, >>, &, ^, |)

Must be written using just bitwise operators -- no loops or if statements (no formal code).