Rotate operand1 left through Carry Flag. The number of rotates is set by operand2.
When immediate is greater then 1, assembler generates several RCL xx, 1 instructions because 8086 has machine code only for this instruction (the same principle works for all other shift/rotate instructions).
RCL memory, immediate RCL REG, immediate RCL memory, CL RCL REG, CL
STC ; set carry (CF=1). MOV AL, 1Ch ; AL = 00011100b RCL AL, 1 ; AL = 00111001b, CF=0. RET