TYA

Transfer Y Index to Accumulator

Opcode: TYA Operation: Y → A Status Register:

TYA (Transfer Y Index to Accumulator) transfers the value in the Y index to the accumulator. The reverse of this opcode is TAY.

Operation

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

unsigned src = Y;             // Load the value of the Y index as an unsigned byte.
SET_NEGATIVE(src);            // Sets the Negative Flag equal to the 7th bit.
SET_ZERO(src);                // Sets the Zero Flag if the Operand is $#00, otherwise clears it.
A = (src);                    // Stores the value of the Y index into the accumulator.

Addressing Modes

Addressing Mode	Assembly Language Form	Opcode	# Bytes	# Cycles
Implied	TYA	98	1	2