There is no "LSL A, 4" instruction. The instruction is "LSL A". One bit shifted per machine instruction.
The swap-plus-bitwise-and is two machine instructions. Bit shifting left four bits is four machine instructions.
There is no "LSL A, 4" instruction. The instruction is "LSL A". One bit shifted per machine instruction.
The swap-plus-bitwise-and is two machine instructions. Bit shifting left four bits is four machine instructions.