Logical instructions are the instructions which perform basic logical operations such as AND, OR, etc. In 8086 microprocessor, the destination operand need not be the accumulator.
Following is the table showing the list of logical instructions:
OPCODE | OPERAND | DESTINATION | EXAMPLE |
---|---|---|---|
AND | D, S | D = D AND S | AND AX, 0010 |
OR | D, S | D = D OR S | OR AX, BX |
NOT | D | D = NOT of D | NOT AL |
XOR | D, S | D = D XOR S | XOR AL, BL |
TEST | D, S | performs bit-wise AND operation and affects the flag registor | TEST [0250], 06 |
SHR | D, C | shifts each bit in D to the right C times and 0 is stored at MSB position | SHR AL, 04 |
SHL | D, C | shifts each bit in D to the left C times and 0 is stored at LSB position | SHL AX, BL |
ROR | D, C | rotates all bits in D to the right C times | ROR BL, CL |
ROL | R, C | rotates all bits in D to the left C times | ROL BX, 06 |
RCR | D, C | rotates all bits in D to the right along with carry flag C times | RCR BL, CL |
RCL | R, C | rotates all bits in D to the left along with carry flag C times | RCL BX, 06 |
Here D stands for destination, S stands for source and C stands for count.
They can either be register, data or memory address.
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