65C02 Opcode matrix:

imm = #$00
zp = $00
zpx = $00,X
zpy = $00,Y
izp = ($00)
izx = ($00,X)
izy = ($00),Y
abs = $0000
abx = $0000,X
aby = $0000,Y
ind = ($0000)
iax = ($0000,X)
rel = $0000 (PC-relative)

  x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF
0x BRK
7		 ORA
izx 6		 NOP
imm 2		 NOP TSB
zp 5		 ORA
zp 3		 ASL
zp 5		 RMB0
zp 5		 PHP
3		 ORA
imm 2		 ASL
2		 NOP TSB
abs 6		 ORA
abs 4		 ASL
abs 6		 BBR0
rel 2*
1x BPL
rel 2*		 ORA
izy 5*		 ORA
izp 5		 NOP TRB
zp 5		 ORA
zpx 4		 ASL
zpx 6		 RMB1
zp 5		 CLC
2		 ORA
aby 4*		 INC
2		 NOP TRB
abs 6		 ORA
abx 4*		 ASL
abx 6*		 BBR1
rel 2*
2x JSR
abs 6		 AND
izx 6		 NOP
imm 2		 NOP BIT
zp 3		 AND
zp 3		 ROL
zp 5		 RMB2
zp 5		 PLP
4		 AND
imm 2		 ROL
2		 NOP BIT
abs 4		 AND
abs 4		 ROL
abs 6		 BBR2
rel 2*
3x BMI
rel 2*		 AND
izy 5*		 AND
izp 5		 NOP BIT
zpx 4		 AND
zpx 4		 ROL
zpx 6		 RMB3
zp 5		 SEC
2		 AND
aby 4*		 DEC
2		 NOP BIT
abx 4*		 AND
abx 4*		 ROL
abx 6*		 BBR3
rel 2*
4x RTI
6		 EOR
izx 6		 NOP
imm 2		 NOP NOP
zp 3		 EOR
zp 3		 LSR
zp 5		 RMB4
zp 5		 PHA
3		 EOR
imm 2		 LSR
2		 NOP JMP
abs 3		 EOR
abs 4		 LSR
abs 6		 BBR4
rel 2*
5x BVC
rel 2*		 EOR
izy 5*		 EOR
izp 5		 NOP NOP
zpx 4		 EOR
zpx 4		 LSR
zpx 6		 RMB5
zp 5		 CLI
2		 EOR
aby 4*		 PHY
3		 NOP NOP EOR
abx 4*		 LSR
abx 6*		 BBR5
rel 2*
6x RTS
6		 ADC
izx 6		 NOP
imm 2		 NOP STZ
zp 3		 ADC
zp 3		 ROR
zp 5		 RMB6
zp 5		 PLA
4		 ADC
imm 2		 ROR
2		 NOP JMP
ind 6		 ADC
abs 4		 ROR
abs 6		 BBR6
rel 2*
7x BVS
rel 2*		 ADC
izy 5*		 ADC
izp 5		 NOP STZ
zpx 4		 ADC
zpx 4		 ROR
zpx 6		 RMB7
zp 5		 SEI
2		 ADC
aby 4*		 PLY
4		 NOP JMP
iax 6		 ADC
abx 4*		 ROR
abx 6*		 BBR7
rel 2*
8x BRA
rel 3*		 STA
izx 6		 NOP
imm 2		 NOP STY
zp 3		 STA
zp 3		 STX
zp 3		 SMB0
zp 5		 DEY
2		 BIT
imm 2		 TXA
2		 NOP STY
abs 4		 STA
abs 4		 STX
abs 4		 BBS0
rel 2*
9x BCC
rel 2*		 STA
izy 6		 STA
izp 5		 NOP STY
zpx 4		 STA
zpx 4		 STX
zpy 4		 SMB1
zp 5		 TYA
2		 STA
aby 5		 TXS
2		 NOP STZ
abs 4		 STA
abx 5		 STZ
abx 5		 BBS1
rel 2*
Ax LDY
imm 2		 LDA
izx 6		 LDX
imm 2		 NOP LDY
zp 3		 LDA
zp 3		 LDX
zp 3		 SMB2
zp 5		 TAY
2		 LDA
imm 2		 TAX
2		 NOP LDY
abs 4		 LDA
abs 4		 LDX
abs 4		 BBS2
rel 2*
Bx BCS
rel 2*		 LDA
izy 5*		 LDA
izp 5		 NOP LDY
zpx 4		 LDA
zpx 4		 LDX
zpy 4		 SMB3
zp 5		 CLV
2		 LDA
aby 4*		 TSX
2		 NOP LDY
abx 4*		 LDA
abx 4*		 LDX
aby 4*		 BBS3
rel 2*
Cx CPY
imm 2		 CMP
izx 6		 NOP
imm 2		 NOP CPY
zp 3		 CMP
zp 3		 DEC
zp 5		 SMB4
zp 5		 INY
2		 CMP
imm 2		 DEX
2		 STP ¹
3		 CPY
abs 4		 CMP
abs 4		 DEC
abs 6		 BBS4
rel 2*
Dx BNE
rel 2*		 CMP
izy 5*		 CMP
izp 5		 NOP NOP
zpx 4		 CMP
zpx 4		 DEC
zpx 6		 SMB5
zp 5		 CLD
2		 CMP
aby 4*		 PHX
3		 WAI ¹
3		 NOP CMP
abx 4*		 DEC
abx 6*		 BBS5
rel 2*
Ex CPX
imm 2		 SBC
izx 6		 NOP
imm 2		 NOP CPX
zp 3		 SBC
zp 3		 INC
zp 5		 SMB6
zp 5		 INX
2		 SBC
imm 2		 NOP
2		 NOP CPX
abs 4		 SBC
abs 4		 INC
abs 6		 BBS6
rel 2*
Fx BEQ
rel 2*		 SBC
izy 5*		 SBC
izp 5		 NOP NOP
zpx 4		 SBC
zpx 4		 INC
zpx 6		 SMB7
zp 5		 SED
2		 SBC
aby 4*		 PLX
4		 NOP NOP SBC
abx 4*		 INC
abx 6*		 BBS7
rel 2*

¹ - Only available on WDC 65C02

"*" : add 1 cycle if page boundary is crossed.
add 1 cycle if direct page register is non zero on direct page adressing modes.
add 1 cycle on conditional branches if taken.
add 1 cycle on these commands if D=1: ADC, SBC


A = Akkumulator
X = X-Register
Y = Y-Register
S = Stack-Pointer
P = Status-Register
+(S) = Stack-Pointer relative with pre-increment
(S)- = Stack-Pointer relative with post-decrement


These things have changed from 6502 to 65C02:

- new instructions.
- new adressing modes for a few instrucions.
- one adressing mode for fetch-modify-write instructions has been optimized, so it takes 1 less cycle in some cases.
- flags now work correctly in BCD mode (takes 1 additional cycle).
- absolute-indirect adressing mode now also works on a page boundary (also 1 additional cycle).
- BRK also affects the decimal flag now.
- illegal opcodes perform a NOP.

 65C02 opcodes:
Opcodeimpimmzpzpx zpyizxizyabsabx abyindrelFunction NVBDIZC
BRA             $80branch always        
PHX$DA             (S)-:=X        
PHY$5A             (S)-:=Y        
PLX$FA             X:=+(S) *    * 
PLY$7A             Y:=+(S) *    * 
STZ  $64$74    $9C$9E    {adr}:=0        
TRB  $14     $1C     {adr}:={adr} nand A      * 
TSB  $04     $0C     {adr}:={adr} or A      * 
BBRn             $xFbranch on bit n reset        
BBSn             $xFbranch on bit n set        
RMBn  $x7           {adr}:={adr} nand 2^n      * 
SMBn  $x7           {adr}:={adr} or 2^n      * 

The WDC 65C02 also includes the STP and WAI instructions known from the 65816.
Another version of this processor, called 65SC02, doesn't have the single-bit instructions BBR/BBS/RMB/SMB.


Changes on instructions of the 6502 instruction set:

INC and DEC now have implied adressing modes.
All major instructions (ORA, ADC, STA...) now also feature the indirect-zeropage adressing mode without index.
JMP features a new absolute-indirect-indexed adressing mode.
BIT now works with a few more adressing modes.


© 2009-2010 Graham. Last change on 17.12.2010.