NOP

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No Operation
Opcode: NOP
Operation: None
Status Register: Status-List.png
Status-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.png

NOP (No Operation) does what it says. When the opcode is executed, the processor does nothing for two clock cycles. This is effective if you want to create a brief delay or make a gap for later additions to machine code.

Because this opcode doesn't do anything, it is a useful way of "commenting out" a section of a game. For example, there is a subroutine that decrements the player's lives, you can change the opcode and operand to NOPs, thus preventing the code from executing, effectively giving the player infinite lives.

Addressing Modes

Addressing Mode Assembly Language Form Opcode # Bytes # Cycles
Implied NOP EA 1 2

Examples