# LDY

Load Index Register Y from Memory

Load index register Y with data from memory.

On all processors, the data loaded from memory is 8-bit. However, for 16-bit processors with the m flag is clear then the data added is 16-bit with the low-order 8-bits at the effective address and the high-order 8-bits at the effective address plus one.

##### Flags Affected

Flags |
| ||||||||
---|---|---|---|---|---|---|---|---|---|

n | Set if most-significant bit of result is set | ||||||||

z | Set if result is zero |

##### Instructions

Syntax | Opcode | Available on: | # of | # of | Addressing Mode | ||
---|---|---|---|---|---|---|---|

(hex) |
6502 | 65C02 | 65816 | bytes | cycles | ||

LDY #const | A0 | x | x | x | 2^{1} |
2^{2} |
Immediate |

LDY addr | AC | x | x | x | 3 | 4^{2} |
Absolute |

LDY dp | A4 | x | x | x | 2 | 3^{2, 3} |
Direct Page |

LDY addr,X | BC | x | x | x | 3 | 4^{2, 4} |
Absolute Indexed X |

LDY dp,X | B4 | x | x | x | 2 | 4^{2, 3} |
Direct Page Indexed X |

### Notes:

- 65816: Add 1 byte if m=0 (16-bit memory/accumulator)
- 65816: Add 1 cycle if m=0 (16-bit memory/accumulator)
- 65816: Add 1 cycle if low byte of Direct Page register is not 0
- Add 1 cycle if adding index crosses a page boundary

Last modified November 5, 2021: Add instruction categories (6b74ff9)