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 / \ /(o)\ /(o)\ /=====\ Call out GANDHU and be happy /=====\ / \ / \ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^