ROL : Rotate Left without Carry: This instruction rotates the content of the destination operand to the left by the specified count bit-wise excluding the carry. The most significant bit is pushed into the carry flag as well as the least significant bit position at each operation. Remaining bits are shifted left subsequently by the specified count positions. Flags PF, SF, and ZF are left unchanged by this rotate operation. The operand may be a register or a memory location. Given figure explains the operation.
Figure : Execution of ROL Instruction