NOP (No OPeration)

NOP is a simple instruction that does nothing. It does not modify any flags, registers, or memory.

The documented NOP instruction takes 2 cycles to complete.

Addressing Modes

Mode	Syntax	Bytes	Cycles
Implied	NOP	EA	2

Undocumented NOP Opcodes

There is only one documented NOP instruction ($EA) but many undocumented opcodes also have no effect. Some take more than 2 cycles to complete, and some read data from memory as if they were other instructions.

Mode	Syntax	Bytes	Cycles
Implied	+NOP	1A	2
Implied	+NOP	3A	2
Implied	+NOP	5A	2
Implied	+NOP	7A	2
Implied	+NOP	DA	2
Implied	+NOP	FA	2
Immediate	+NOP #const	80 nn	2
Immediate	+NOP #const	82 nn	2
Immediate	+NOP #const	89 nn	2
Immediate	+NOP #const	C2 nn	2
Immediate	+NOP #const	E2 nn	2
ZeroPage	+NOP zp	04 nn	3
ZeroPage	+NOP zp	44 nn	3
ZeroPage	+NOP zp	64 nn	3
ZeroPage+X	+NOP zp,x	14 nn	4
ZeroPage+X	+NOP zp,x	34 nn	4
ZeroPage+X	+NOP zp,x	54 nn	4
ZeroPage+X	+NOP zp,x	74 nn	4
ZeroPage+X	+NOP zp,x	D4 nn	4
ZeroPage+X	+NOP zp,x	F4 nn	4
Absolute	+NOP addr	0C ll hh	3
Absolute+X	+NOP addr,x	1C ll hh	4
Absolute+X	+NOP addr,x	3C ll hh	4
Absolute+X	+NOP addr,x	5C ll hh	4
Absolute+X	+NOP addr,x	7C ll hh	4
Absolute+X	+NOP addr,x	DC ll hh	4
Absolute+X	+NOP addr,x	FC ll hh	4

Comments