For others reading, it's making a call in both cases because "integer" is not a native machine type. Integers are unbounded and include all big integers as wel

For others reading, it's making a call in both cases because "integer" is not a native machine type. Integers are unbounded and include all big integers as well. The various float types and fixnum (machine register width integer) would compile down to machine code multiplication instructions without function calls, if declared or inferred that the inputs (and output in the fixnum case) are of those types, and the safety option is reduced. (In SBCL)