Logical Instructions in AVR Microcontroller

Logical Instructions are the instructions which perform basic arithmetic operations such as AND, OR, XOR, etc. In AVR micro-controller, the destination operand is always a register.

The following table shows the logical instructions :

Instruction	Operand	Explanation	Example
AND	D, S	D = D AND S Performs a AND operation on the operands and stores the result in the left hand operand	AND D, S
ANDI	D, k(constant)	D = D AND k Performs a AND operation on the operands and stores the result in the left hand operand with the right hand operand being a constant	ANDI D, k
OR	D, S	D = D OR S Performs a OR operation on the operands and stores the result in the left hand operand	OR D, S
ORI	D, k	D = D OR k Performs a OR operation on the operands and stores the result in the left hand operand with the right hand operand being a constant	ORI D, k
EOR	D, S	D = D XOR S Performs a EX-OR operation on the operands and stores the result in the left hand operand	EOR D, S
COM	D.	D = 1’s complement of D The complement action changes ‘1’s to ‘0’s and ‘0’s to ‘1’s	COM D
NEG	D	D = 2’s complement of D This instruction takes the 2’s complement	NEG D
CP	D, S	Compares D and S This instruction is really a subtraction action. The only difference is that the values of registers don’t change	CP D, S
CPI	D, k	Compares D and k The only difference between CP an CPI is that CPI has one of the operands as a constant	CP D, k

Note :
D and S are Destination and Source respectively. Both are registers. k is a constant.