For ease of cycle counting, I've created the following opcode table. Note:
the cycles given are color cycles, not CPU cycles. I also haven't included
any of the undocumented/illegal opcodes.
Imp Imm Zp ZpX Abs AbX AbY Ind InX InY
bytes 1 2 2 2 3 3 3 3 2 2
ADC 6 9 12 12 12+3 12+3 18 15+3
AND 6 6 9 12 12+3 12+3 18 15+3
ASL 6 (A) 15 18 18 21
BIT 9 12
BRA 6/9+3 (BMI,BPL,BVS,BVC,BNE,BEQ,BCS,BCC)
BRK 21
CMP 6 9 12 12 12+3 12+3 18 15+3
CPX 6 9 12
CPY 6 9 12
DEC 6 (XY) 15 18 18 21
EOR 6 9 12 12 12+3 12+3 18 15+3
FLAG 6 (CLV,SED,CLD,SEI,CLI,CLC,SEC)
INC 6 (XY) 15 18 18 21
JMP 9 15
JSR 9
LDA 6 9 12 12 12+3 12+3 18 15+3
LDX 6 9 12 ZpY 12 12+3
LDY 6 9 12 12 12+3
LSR 6 (A) 15 18 18 21
NOP 6
ORA 6 6 9 12 12+3 12+3 18 15+3
PHA 9 (push A)
PHP 9 (push condition code)
PLA 12 (pop A)
PLP 12 (pop codition code)
ROL 6 (A) 15 18 18 21
ROR 6 (A) 15 18 18 21
RTI 18
RTS 18
STA 9 12 12 15 15 18 18
SBC 6 9 12 12 12+3 12+3 18 15+3
STX 9 12 ZpY 12
STY 9 12 12
TRAN 6 (TAX, TXA, TAY, TYA, TXS, TSX)
The shorthand should be familiar to anyone who has used other opcode
tables, but for completeness:
Imp implicit, opcode only (including INX, INY, DEX, DEY)
Imm immediate data (relative for branch)
Zp zero page memory
ZpX zero page address + X
ZpY zero page address + Y (only used by LDX & STX)
Abs absolute address
AbX absolute address + X (extra 3 cycles for over page boundary)
AbY absolute address + Y (extra 3 cycles for over page boundary)
Ind indirect (absolute address)
InX indirect (Zp + X) (extra 3 cycles for over page boundary)
InY indirect (Zp) + Y (extra 3 cycles for over page boundary)
Branches are 6 cycles if not taken, 9 if taken and 12 if taken over a page
boundary
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