EOR

Exclusive OR Memory With Accumulator

Opcode: EOR Operation: A ^ M → A Status Register:

EOR (Exclusive OR Memory With Accumulator) performs a logical XOR on the operand and the accumulator and stores the result in the accumulator. This opcode is similar in function to AND and ORA.

Operation

This pseudo C code shows how the EOR opcode functions when it is executed.

Operand ^= ACCUMULATOR        // XOR the two values together.
SET_NEGATIVE(Operand);        // Clears the Negative Flag if the Operand is $#00-7F, otherwise sets it.
SET_ZERO(Operand);            // Sets the Zero Flag if the Operand is $#00, otherwise clears it.
ACCUMULATOR = Operand;        // Stores the Operand in the Accumulator Register.

Addressing Modes

Addressing Mode	Assembly Language Form	Opcode	# Bytes	# Cycles
Immediate	EOR #Operand	49	2	2
Zero Page	EOR Operand	45	2	3
Zero Page, X	EOR Operand, X	55	2	4
Absolute	EOR Operand	4D	3	4
Absolute, X	EOR Operand, X	5D	3	4*
Absolute, Y	EOR Operand, Y	59	3	4*
(Indirect, X)	EOR (Operand, X)	41	2	6
(Indirect), Y	EOR (Operand), Y	51	2	5*
* Add 1 if page boundary is crossed.