LDY (LoaD Y register)¶

Y = [operand]

LDY (LoaD Y register) is an instruction that loads a value from memory into the Y register. The operand can be either an immediate value, a memory location specified by its address, or a memory location specified by an indexed indirect or indirect indexed address.

The result is stored in the Y register, and the Zero and Negative flags are set based on the result.

Addressing Modes¶

Mode	Syntax	Bytes	Cycles
Immediate	LDY #const	`A0 nn`	2
ZeroPage	LDY zp	`A4 nn`	3
ZeroPage+X	LDY zp,x	`B4 nn`	4
Absolute	LDY addr	`AC ll hh`	4
Absolute+X	LDY addr,x	`BC ll hh`	4-5

Flags Affected¶

N (Negative) – Set if the loaded value has the most significant bit set (i.e., is negative); otherwise, it is cleared.
Z (Zero) – Set if the loaded value is zero; otherwise, it is cleared.

Examples¶

Load a Constant into the Y Register¶

    LDY #10    ; load Y with constant 10

Load a Value from a Memory Location¶

    LDY $20    ; load Y with the value at memory location $20

Load a Value from a Memory Location with an Offset¶

    LDX #2     ; load X with 2
    LDY $10,X  ; load Y with the value at memory location $12 ($10 + X)