Command: SHL- Shift logical left
Arguments: OP: register or memory location; QUANTITY: immediate
Usage: SHL OP, QUANTITY
Effects: Shifts all bits of OP left QUANTITY times and adds a 0 at the beginning.
Flags to be set: OF, SF, ZF, PF, CF
Misc: Carry flag contains bit that was shifted out last.
Corresponds to multiply by 2 QUANTITY times