6502 Opcodes and Quasi-Opcodes.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The following table lists all of the available opcodes on the 65xx line of
micro-processors (such as the 6510 on the C=64 and the 8502 on the C=128)
-----------------------------------------------------------------------------
Std Mnemonic Hex Value Description Addressing Mode Bytes/Time
* BRK $00 Stack <- PC, PC <- ($fffe) (Immediate) 1/7
* ORA $01 A <- (A) V M (Ind,X) 6/2
JAM $02 [locks up machine] (Implied) 1/-
SLO $03 M <- (M >> 1) + A + C (Ind,X) 2/8
NOP $04 [no operation] (Z-Page) 2/3
* ORA $05 A <- (A) V M (Z-Page) 2/3
* ASL $06 C <- A7, A <- (A) << 1 (Z-Page) 2/5
SLO $07 M <- (M >> 1) + A + C (Z-Page) 2/5
* PHP $08 Stack <- (P) (Implied) 1/3
* ORA $09 A <- (A) V M (Immediate) 2/2
* ASL $0A C <- A7, A <- (A) << 1 (Accumalator) 1/2
ANC $0B A <- A /\ M, C=~A7 (Immediate) 1/2
NOP $0C [no operation] (Absolute) 3/4
* ORA $0D A <- (A) V M (Absolute) 3/4
* ASL $0E C <- A7, A <- (A) << 1 (Absolute) 3/6
SLO $0F M <- (M >> 1) + A + C (Absolute) 3/6
* BPL $10 if N=0, PC = PC + offset (Relative) 2/2'2
* ORA $11 A <- (A) V M ((Ind),Y) 2/5'1
JAM $12 [locks up machine] (Implied) 1/-
SLO $13 M <- (M >. 1) + A + C ((Ind),Y) 2/8'5
NOP $14 [no operation] (Z-Page,X) 2/4
* ORA $15 A <- (A) V M (Z-Page,X) 2/4
* ASL $16 C <- A7, A <- (A) << 1 (Z-Page,X) 2/6
SLO $17 M <- (M >> 1) + A + C (Z-Page,X) 2/6
* CLC $18 C <- 0 (Implied) 1/2
* ORA $19 A <- (A) V M (Absolute,Y) 3/4'1
NOP $1A [no operation] (Implied) 1/2
SLO $1B M <- (M >> 1) + A + C (Absolute,Y) 3/7
NOP $1C [no operation] (Absolute,X) 2/4'1
* ORA $1D A <- (A) V M (Absolute,X) 3/4'1
* ASL $1E C <- A7, A <- (A) << 1 (Absolute,X) 3/7
SLO $1F M <- (M >> 1) + A + C (Absolute,X) 3/7
* JSR $20 Stack <- PC, PC <- Address (Absolute) 3/6
* AND $21 A <- (A) /\ M (Ind,X) 2/6
JAM $22 [locks up machine] (Implied) 1/-
RLA $23 M <- (M << 1) /\ (A) (Ind,X) 2/8
* BIT $24 Z <- ~(A /\ M) N<-M7 V<-M6 (Z-Page) 2/3
* AND $25 A <- (A) /\ M (Z-Page) 2/3
* ROL $26 C <- A7 & A <- A << 1 + C (Z-Page) 2/5
RLA $27 M <- (M << 1) /\ (A) (Z-Page) 2/5'5
* PLP $28 A <- (Stack) (Implied) 1/4
* AND $29 A <- (A) /\ M (Immediate) 2/2
* ROL $2A C <- A7 & A <- A << 1 + C (Accumalator) 1/2
ANC $2B A <- A /\ M, C <- ~A7 (Immediate9 1/2
* BIT $2C Z <- ~(A /\ M) N<-M7 V<-M6 (Absolute) 3/4
* AND $2D A <- (A) /\ M (Absolute) 3/4
* ROL $2E C <- A7 & A <- A << 1 + C (Absolute) 3/6
RLA $2F M <- (M << 1) /\ (A) (Absolute) 3/6'5
* BMI $30 if N=1, PC = PC + offset (Relative) 2/2'2
* AND $31 A <- (A) /\ M ((Ind),Y) 2/5'1
JAM $32 [locks up machine] (Implied) 1/-
RLA $33 M <- (M << 1) /\ (A) ((Ind),Y) 2/8'5
NOP $34 [no operation] (Z-Page,X) 2/4
* AND $35 A <- (A) /\ M (Z-Page,X) 2/4
* ROL $36 C <- A7 & A <- A << 1 + C (Z-Page,X) 2/6
RLA $37 M <- (M << 1) /\ (A) (Z-Page,X) 2/6'5
* SEC $38 C <- 1 (Implied) 1/2
* AND $39 A <- (A) /\ M (Absolute,Y) 3/4'1
NOP $3A [no operation] (Implied) 1/2
RLA $3B M <- (M << 1) /\ (A) (Absolute,Y) 3/7'5
NOP $3C [no operation] (Absolute,X) 3/4'1
* AND $3D A <- (A) /\ M (Absolute,X) 3/4'1
* ROL $3E C <- A7 & A <- A << 1 + C (Absolute,X) 3/7
RLA $3F M <- (M << 1) /\ (A) (Absolute,X) 3/7'5
* RTI $40 P <- (Stack), PC <-(Stack) (Implied) 1/6
* EOR $41 A <- (A) \-/ M (Ind,X) 2/6
JAM $42 [locks up machine] (Implied) 1/-
SRE $43 M <- (M >> 1) \-/ A (Ind,X) 2/8
NOP $44 [no operation] (Z-Page) 2/3
* EOR $45 A <- (A) \-/ M (Z-Page) 2/3
* LSR $46 C <- A0, A <- (A) >> 1 (Absolute,X) 3/7
SRE $47 M <- (M >> 1) \-/ A (Z-Page) 2/5
* PHA $48 Stack <- (A) (Implied) 1/3
* EOR $49 A <- (A) \-/ M (Immediate) 2/2
* LSR $4A C <- A0, A <- (A) >> 1 (Accumalator) 1/2
ASR $4B A <- [(A /\ M) >> 1] (Immediate) 1/2
* JMP $4C PC <- Address (Absolute) 3/3
* EOR $4D A <- (A) \-/ M (Absolute) 3/4
* LSR $4E C <- A0, A <- (A) >> 1 (Absolute) 3/6
SRE $4F M <- (M >> 1) \-/ A (Absolute) 3/6
* BVC $50 if V=0, PC = PC + offset (Relative) 2/2'2
* EOR $51 A <- (A) \-/ M ((Ind),Y) 2/5'1
JAM $52 [locks up machine] (Implied) 1/-
SRE $53 M <- (M >> 1) \-/ A ((Ind),Y) 2/8
NOP $54 [no operation] (Z-Page,X) 2/4
* EOR $55 A <- (A) \-/ M (Z-Page,X) 2/4
* LSR $56 C <- A0, A <- (A) >> 1 (Z-Page,X) 2/6
SRE $57 M <- (M >> 1) \-/ A (Z-Page,X) 2/6
* CLI $58 I <- 0 (Implied) 1/2
* EOR $59 A <- (A) \-/ M (Absolute,Y) 3/4'1
NOP $5A [no operation] (Implied) 1/2
SRE $5B M <- (M >> 1) \-/ A (Absolute,Y) 3/7
NOP $5C [no operation] (Absolute,X) 3/4'1
* EOR $5D A <- (A) \-/ M (Absolute,X) 3/4'1
SRE $5F M <- (M >> 1) \-/ A (Absolute,X) 3/7
* RTS $60 PC <- (Stack) (Implied) 1/6
* ADC $61 A <- (A) + M + C (Ind,X) 2/6
JAM $62 [locks up machine] (Implied) 1/-
RRA $63 M <- (M >> 1) + (A) + C (Ind,X) 2/8'5
NOP $64 [no operation] (Z-Page) 2/3
* ADC $65 A <- (A) + M + C (Z-Page) 2/3
* ROR $66 C<-A0 & A<- (A7=C + A>>1) (Z-Page) 2/5
RRA $67 M <- (M >> 1) + (A) + C (Z-Page) 2/5'5
* PLA $68 A <- (Stack) (Implied) 1/4
* ADC $69 A <- (A) + M + C (Immediate) 2/2
* ROR $6A C<-A0 & A<- (A7=C + A>>1) (Accumalator) 1/2
ARR $6B A <- [(A /\ M) >> 1] (Immediate) 1/2'5
* JMP $6C PC <- Address (Indirect) 3/5
* ADC $6D A <- (A) + M + C (Absolute) 3/4
* ROR $6E C<-A0 & A<- (A7=C + A>>1) (Absolute) 3/6
RRA $6F M <- (M >> 1) + (A) + C (Absolute) 3/6'5
* BVS $70 if V=1, PC = PC + offset (Relative) 2/2'2
* ADC $71 A <- (A) + M + C ((Ind),Y) 2/5'1
JAM $72 [locks up machine] (Implied) 1/-
RRA $73 M <- (M >> 1) + (A) + C ((Ind),Y) 2/8'5
NOP $74 [no operation] (Z-Page,X) 2/4
* ADC $75 A <- (A) + M + C (Z-Page,X) 2/4
* ROR $76 C<-A0 & A<- (A7=C + A>>1) (Z-Page,X) 2/6
RRA $77 M <- (M >> 1) + (A) + C (Z-Page,X) 2/6'5
* SEI $78 I <- 1 (Implied) 1/2
* ADC $79 A <- (A) + M + C (Absolute,Y) 3/4'1
NOP $7A [no operation] (Implied) 1/2
RRA $7B M <- (M >> 1) + (A) + C (Absolute,Y) 3/7'5
NOP $7C [no operation] (Absolute,X) 3/4'1
* ADC $7D A <- (A) + M + C (Absolute,X) 3/4'1
* ROR $7E C<-A0 & A<- (A7=C + A>>1) (Absolute,X) 3/7
RRA $7F M <- (M >> 1) + (A) + C (Absolute,X) 3/7'5
NOP $80 [no operation] (Immediate) 2/2
* STA $81 M <- (A) (Ind,X) 2/6
NOP $82 [no operation] (Immediate) 2/2
SAX $83 M <- (A) /\ (X) (Ind,X) 2/6
* STY $84 M <- (Y) (Z-Page) 2/3
* STA $85 M <- (A) (Z-Page) 2/3
* STX $86 M <- (X) (Z-Page) 2/3
SAX $87 M <- (A) /\ (X) (Z-Page) 2/3
* DEY $88 Y <- (Y) - 1 (Implied) 1/2
NOP $89 [no operation] (Immediate) 2/2
* TXA $8A A <- (X) (Implied) 1/2
ANE $8B M <-[(A)\/$EE] /\ (X)/\(M) (Immediate) 2/2^4
* STY $8C M <- (Y) (Absolute) 3/4
* STA $8D M <- (A) (Absolute) 3/4
* STX $8E M <- (X) (Absolute) 3/4
SAX $8F M <- (A) /\ (X) (Absolute) 3/4
* BCC $90 if C=0, PC = PC + offset (Relative) 2/2'2
* STA $91 M <- (A) ((Ind),Y) 2/6
JAM $92 [locks up machine] (Implied) 1/-
SHA $93 M <- (A) /\ (X) /\ (PCH+1) (Absolute,X) 3/6'3
* STY $94 M <- (Y) (Z-Page,X) 2/4
* STA $95 M <- (A) (Z-Page,X) 2/4
SAX $97 M <- (A) /\ (X) (Z-Page,Y) 2/4
* STX $96 M <- (X) (Z-Page,Y) 2/4
* TYA $98 A <- (Y) (Implied) 1/2
* STA $99 M <- (A) (Absolute,Y) 3/5
* TXS $9A S <- (X) (Implied) 1/2
SHS $9B X <- (A) /\ (X), S <- (X) (Absolute,Y) 3/5
M <- (X) /\ (PCH+1)
SHY $9C M <- (Y) /\ (PCH+1) (Absolute,Y) 3/5'3
* STA $9D M <- (A) (Absolute,X) 3/5
SHX $9E M <- (X) /\ (PCH+1) (Absolute,X) 3/5'3
SHA $9F M <- (A) /\ (X) /\ (PCH+1) (Absolute,Y) 3/5'3
* LDY $A0 Y <- M (Immediate) 2/2
* LDA $A1 A <- M (Ind,X) 2/6
* LDX $A2 X <- M (Immediate) 2/2
LAX $A3 A <- M, X <- M (Ind,X) 2/6
* LDY $A4 Y <- M (Z-Page) 2/3
* LDA $A5 A <- M (Z-Page) 2/3
* LDX $A6 X <- M (Z-Page) 2/3
LAX $A7 A <- M, X <- M (Z-Page) 2/3
* TAY $A8 Y <- (A) (Implied) 1/2
* LDA $A9 A <- M (Immediate) 2/2
* TAX $AA X <- (A) (Implied) 1/2
LXA $AB X04 <- (X04) /\ M04 (Immediate) 1/2
A04 <- (A04) /\ M04
* LDY $AC Y <- M (Absolute) 3/4
* LDA $AD A <- M (Absolute) 3/4
* LDX $AE X <- M (Absolute) 3/4
LAX $AF A <- M, X <- M (Absolute) 3/4
* BCS $B0 if C=1, PC = PC + offset (Relative) 2/2'2
* LDA $B1 A <- M ((Ind),Y) 2/5'1
JAM $B2 [locks up machine] (Implied) 1/-
LAX $B3 A <- M, X <- M ((Ind),Y) 2/5'1
* LDY $B4 Y <- M (Z-Page,X) 2/4
* LDA $B5 A <- M (Z-Page,X) 2/4
* LDX $B6 X <- M (Z-Page,Y) 2/4
LAX $B7 A <- M, X <- M (Z-Page,Y) 2/4
* CLV $B8 V <- 0 (Implied) 1/2
* LDA $B9 A <- M (Absolute,Y) 3/4'1
* TSX $BA X <- (S) (Implied) 1/2
LAE $BB X,S,A <- (S /\ M) (Absolute,Y) 3/4'1
* LDY $BC Y <- M (Absolute,X) 3/4'1
* LDA $BD A <- M (Absolute,X) 3/4'1
* LDX $BE X <- M (Absolute,Y) 3/4'1
LAX $BF A <- M, X <- M (Absolute,Y) 3/4'1
* CPY $C0 (Y - M) -> NZC (Immediate) 2/2
* CMP $C1 (A - M) -> NZC (Ind,X) 2/6
NOP $C2 [no operation] (Immediate) 2/2
DCP $C3 M <- (M)-1, (A-M) -> NZC (Ind,X) 2/8
* CPY $C4 (Y - M) -> NZC (Z-Page) 2/3
* CMP $C5 (A - M) -> NZC (Z-Page) 2/3
* DEC $C6 M <- (M) - 1 (Z-Page) 2/5
DCP $C7 M <- (M)-1, (A-M) -> NZC (Z-Page) 2/5
* INY $C8 Y <- (Y) + 1 (Implied) 1/2
* CMP $C9 (A - M) -> NZC (Immediate) 2/2
* DEX $CA X <- (X) - 1 (Implied) 1/2
SBX $CB X <- (X)/\(A) - M (Immediate) 2/2
* CPY $CC (Y - M) -> NZC (Absolute) 3/4
* CMP $CD (A - M) -> NZC (Absolute) 3/4
* DEC $CE M <- (M) - 1 (Absolute) 3/6
DCP $CF M <- (M)-1, (A-M) -> NZC (Absolute) 3/6
* BNE $D0 if Z=0, PC = PC + offset (Relative) 2/2'2
* CMP $D1 (A - M) -> NZC ((Ind),Y) 2/5'1
JAM $D2 [locks up machine] (Implied) 1/-
DCP $D3 M <- (M)-1, (A-M) -> NZC ((Ind),Y) 2/8
NOP $D4 [no operation] (Z-Page,X) 2/4
* CMP $D5 (A - M) -> NZC (Z-Page,X) 2/4
* DEC $D6 M <- (M) - 1 (Z-Page,X) 2/6
DCP $D7 M <- (M)-1, (A-M) -> NZC (Z-Page,X) 2/6
* CLD $D8 D <- 0 (Implied) 1/2
* CMP $D9 (A - M) -> NZC (Absolute,Y) 3/4'1
NOP $DA [no operation] (Implied) 1/2
DCP $DB M <- (M)-1, (A-M) -> NZC (Absolute,Y) 3/7
NOP $DC [no operation] (Absolute,X) 3/4'1
* CMP $DD (A - M) -> NZC (Absolute,X) 3/4'1
* DEC $DE M <- (M) - 1 (Absolute,X) 3/7
DCP $DF M <- (M)-1, (A-M) -> NZC (Absolute,X) 3/7
* CPX $E0 (X - M) -> NZC (Immediate) 2/2
* SBC $E1 A <- (A) - M - ~C (Ind,X) 2/6
NOP $E2 [no operation] (Immediate) 2/2
ISB $E3 M <- (M) - 1,A <- (A)-M-~C (Ind,X) 3/8'1
* CPX $E4 (X - M) -> NZC (Z-Page) 2/3
* SBC $E5 A <- (A) - M - ~C (Z-Page) 2/3
* INC $E6 M <- (M) + 1 (Z-Page) 2/5
ISB $E7 M <- (M) - 1,A <- (A)-M-~C (Z-Page) 2/5
* INX $E8 X <- (X) +1 (Implied) 1/2
* SBC $E9 A <- (A) - M - ~C (Immediate) 2/2
* NOP $EA [no operation] (Implied) 1/2
SBC $EB A <- (A) - M - ~C (Immediate) 1/2
* SBC $ED A <- (A) - M - ~C (Absolute) 3/4
* CPX $EC (X - M) -> NZC (Absolute) 3/4
* INC $EE M <- (M) + 1 (Absolute) 3/6
ISB $EF M <- (M) - 1,A <- (A)-M-~C (Absolute) 3/6
* BEQ $F0 if Z=1, PC = PC + offset (Relative) 2/2'2
* SBC $F1 A <- (A) - M - ~C ((Ind),Y) 2/5'1
JAM $F2 [locks up machine] (Implied) 1/-
ISB $F3 M <- (M) - 1,A <- (A)-M-~C ((Ind),Y) 2/8
NOP $F4 [no operation] (Z-Page,X) 2/4
* SBC $F5 A <- (A) - M - ~C (Z-Page,X) 2/4
* INC $F6 M <- (M) + 1 (Z-Page,X) 2/6
ISB $F7 M <- (M) - 1,A <- (A)-M-~C (Z-Page,X) 2/6
* SED $F8 D <- 1 (Implied) 1/2
* SBC $F9 A <- (A) - M - ~C (Absolute,Y) 3/4'1
NOP $FA [no operation] (Implied) 1/2
ISB $FB M <- (M) - 1,A <- (A)-M-~C (Absolute,Y) 3/7
NOP $FC [no operation] (Absolute,X) 3/4'1
* SBC $FD A <- (A) - M - ~C (Absolute,X) 3/4'1
* INC $FE M <- (M) + 1 (Absolute,X) 3/7
ISB $FF M <- (M) - 1,A <- (A)-M-~C (Absolute,X) 3/7
'1 - Add one if address crosses a page boundry.
'2 - Add 1 if branch succeeds, or 2 if into another page.
'3 - If page boundry crossed then PCH+1 is just PCH
'4 - Sources disputed on exact operation, or sometimes does not work.
'5 - Full eight bit rotation (with carry)
Sources:
Programming the 6502, Rodney Zaks, (c) 1983 Sybex
Paul Ojala, Post to Comp.Sys.Cbm (po87553@xxxxxxxxx / albert@xxxxxxxxx)
D John Mckenna, Post to Comp.Sys.Cbm (gudjm@xxxxxxxxxxxxxxx)
Compiled by Craig Taylor (duck@xxxxxxxxxxxxxxxxxxxxx)
AD> I was figuring, if one is going to go down the illegal opcode path... then
AD> why not go the whole hog. A search of the 'net has failed to dredge up the
AD> info I need, and I'm hoping somebody on the list can help out. I recall
AD> many years ago two illegal 6502 instructions I'm hoping are available for
AD> the 2600... those were XXY and one I can't remember the mnemonic of. XXY
AD> simply exchanged X and Y registers... handy! The other swapped nibbles on
AD> the accumulator... VERY handy.
AD> That is, given a byte $AB, after that instruction you would have $BA.
AD> Hoping somebody can help (or be bothered trying to find the instructions!!)
AD> Cheers
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