STY (STore Y register)

[operand] = Y

The STY instruction transfers the contents of the Y register to the specified memory location. The operand specifies the memory location where the data is to be stored.

Addressing Modes

Mode	Syntax	Bytes	Cycles
ZeroPage	STY zp	84 nn	3
ZeroPage+X	STY zp,x	94 nn	4
Absolute	STY addr	8C ll hh	4

Flags Affected

None.

Examples

Storing a Value to a Memory Location

    LDY #10     ; load Y with constant 10
    STY $40     ; store the value of Y to memory location $40

Storing the Y Register to an Absolute Address

    STY $2000   ; store the value of Y to memory location $2000

Storing the Y Register to a Zero-Page Address

    STY $40     ; store the value of Y to memory location $40

Storing the Y Register to an Address Indexed by X

    LDY #10     ; load Y with constant 10
    LDX #2      ; load X with constant 2
    STY $40,X   ; store the value of Y to memory location $42 (assuming X = 2)

See Also

• LDA (LoaD Accumulator)

• STA (STore Accumulator)

• STX (STore X register)

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