BBC Emulator Development List:
Mike Borcherds mailto:borchrds.teaching@physics.oxford.ac.uk
Fri, 23 Sep 94 12:56:54 +0100
UNDOCUMENTED 6502 OP-CODES
Those prefixed with a * still represent illegal instructions on the
65C02, but do not necessarily perform the same function as on the 6502.
Those without a * symbol are new, legal 65C02 op-codes, see second
column.
C Op. Instruction (6502) Instruction (65C02)
* 02 HALT ?
* 03 ASL-ORA ind,X ?
04 NOP (2) zp TSB zp
07 ASL-ORA zp RMB 0 zp
* 0B AND imm ?
0C NOP (3) abs TSB abs
0F ASL-ORA abs BBR 0 mask rel
12 HALT ORA (zp)
* 13 ASL-ORA abs,Y ?
14 NOP (2) zp TRB zp
17 ASL-ORA zp,X RMB 1 zp
1A NOP INC A
* 1B ASL-ORA abs,Y ?
1C NOP (3) abs TRB abs
1F ASL-ORA abs,X BBR 1 mask rel
* 22 HALT ?
* 23 ROL-AND ind,X ?
27 ROL-AND zp RMB 2 zp
* 2B AND imm ?
2F ROL-AND abs BBR 2 mask rel
32 HALT AND (zp)
* 33 ROL-AND ind,Y ?
34 NOP (2) zp BIT zp,X
37 ROL-AND zp,X RMB 3 zp
38 SEC SEC
3A NOP DEC A
* 3B ROL-ORA abs,Y ?
3C NOP (3) abs BIT abs,X
3F ROL-AND abs,X BBR 3 mask rel
* 42 HALT ?
* 43 LSR-EOR ind,X ?
* 44 NOP (2) zp ?
47 LSR-EOR zp RMB 4 zp
* 4B AND-LSR imm ?
4F LSR-EOR abs BBR 4 mask rel
52 HALT EOR (zp)
* 53 LSR-EOR ind,Y ?
* 54 NOP (2) zp ?
* 57 LSR-EOR abs,Y ?
5A NOP PHY
* 5B LSR-EOR abs,Y ?
* 5C NOP (3) abs ?
5F LSR-EOR abs,X BBR 5 mask rel
* 62 HALT ?
* 63 ROR-ADC ind,X ?
64 ? STZ zp
67 ROR-ADC zp RMB 6 zp
* 6B ? ?
6C JMP ind JMP (abs)
6F ROR-ADC abs BBR 6 mask rel
72 HALT ADC (zp)
* 73 ROR-ADC ind,Y ?
74 NOP (2) zp STZ zp,X
77 ROR-ADC zp,X RMB 7 zp
7A NOP PLY
* 7B ROR-ADC abs,Y ?
7C NOP (3) abs JMP (abs,X)
7F ROR-ADC abs,X BBR 7 mask rel
80 NOP (2) zp BRA rel
* 82 HALT ?
* 83 ? ?
87 STA-STX zp SMB 0 zp
89 NOP (2) zp BIT #n
* 8B TXA-AND imm ?
8F STA-STX abs BBS 0 mask rel
92 HALT STA (zp)
* 93 ? ?
97 STA-STX zp,Y SMB 1 zp
* 9B ? ?
9C STZ abs STZ abs
9E ? STZ abs,X
9F STA-STX abs,X BBS 1 mask rel
* A3 LDX-LDA ind,X ?
A7 LDX-LDA zp SMB 2 zp
A8 TAY TAY
AF LDX-LDA abs BBS 2 mask rel
B2 HALT LDA (zp)
* B3 LDX-LDA ind,Y ?
B7 LDX-LDA zp,Y SMB 3 zp
* BB ? ?
BF LDX-LDA abs,Y BBS 3 mask rel
* C2 HALT ?
* C3 DEC-CMP ind,X ?
C7 DEC-CMP zp SMB 4 zp
* CB SBX imm ?
CF DEC-CMP abs BBS 4 mask rel
D2 HALT CMP (zp)
* D3 DEC-CMP ind,Y ?
* D4 ? ?
D7 DEC-CMP zp,X SMB 5 zp
DA NOP PHX
* DB DEC-CMP abs,Y ?
* DC NOP (3) abs ?
DF DEC-CMP abs,X BBS 5 mask rel
* E2 HALT ?
* E3 INC-SBC ind,X ?
E7 INC-SBC zp SMB 6 zp
* EB SBC imm ?
EF INC-SBC abs BBS 6 mask rel
F2 HALT SBC (zp)
* F3 INC-SBC ind,Y ?
* F4 NOP (2) zp ?
F7 INC-SBC zp,X SMB 7 zp
F8 SED SED
FA NOP PLX
* FC NOP (3) abs ?
FF INC-SBC abs,X BBS 7 mask rel
--
Martin Ebourne "Pray that there's intelligent
Electronics, life somehere out in space,
Southampton University because there's bugger all
Email: mje@soton.ac.uk down here on earth." - Python
. ** Tom Seddon ** .
/ \ E-mail: T.W.Seddon@ncl.ac.uk / \
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