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CMP: Difference between revisions

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'''CMP''' (Compare) is a 65x instruction that compares the value of the [[accumulator]].
'''CMP''' (Compare) is a 65x instruction that compares the value of the [[accumulator]]. In [[immediate addressing]] only, CMP is a total of 3 bytes long when the accumulator is 16 bits wide.
 
===== Cycle Penalties =====
* In all [[addressing modes]], CMP takes an extra cycle when the accumulator is 16 bits wide
* In [[direct page addressing]] modes, CMP takes an extra cycle when the low byte of the [[direct page register]] is nonzero
* In both [[Absolute Indexed]] and DP Indirect Indexed by Y, CMP takes an extra cycle if adding the index crosses a page boundary


=== See Also ===
=== See Also ===

Revision as of 05:06, 20 November 2023

Basic Info
Addressing Mode Opcode Length Speed
Immediate C9 2 bytes* 2 cycles*
Absolute CD 3 bytes 4 cycles*
absolute long CF 4 bytes 5 cycles*
direct page C5 2 bytes 3 cycles*
direct page indirect D2 2 bytes 5 cycles*
direct page indirect long C7 2 bytes 6 cycles*
absolute indexed by X DD 3 bytes 4 cycles*
absolute long indexed by X DF 4 bytes 5 cycles*
absolute indexed by Y D9 3 bytes 4 cycles*
direct page indexed by X D5 2 bytes 4 cycles*
direct page indexed indirect by X C1 2 bytes 6 cycles*
direct page indirect indexed by Y D1 2 bytes 5 cycles*
direct page indirect long indexed by Y D7 2 bytes 6 cycles*
stack relative C3 2 bytes 4 cycles*
stack relative indirect indexed by Y D3 2 bytes 7 cycles*
Flags Affected
N V M X D I Z C
. . . . .

CMP (Compare) is a 65x instruction that compares the value of the accumulator. In immediate addressing only, CMP is a total of 3 bytes long when the accumulator is 16 bits wide.

Cycle Penalties

See Also

External Links

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