Instruction set Lookup Table¶
| I-Len | T-Cnt |
| Mnemonic | |
| Address Mode | |
- I-Len
- Instruction length. The number of bytes of memory required to store the instruction.
- T-Cnt
- Timing Cycle (T-State) count. The number of clock cycles required to execute the instruction.
- Mnemonic
- The abbreviated “human readable” identity of the instruction.
- Address Mode
- The memory addressing mode used by the instruction.
The opcode for any instruction may be composed by reading the row and column it is in:
ASLin Absolute addressing mode is in row1-, column-E- Therefore it’s opcode (hexadecimal representation) is
1E(or$1Eor0x1E)
Some instructions (or more specifically Addressing Modes) require either one or two bytes of data as a parameter.
Under these circumstances, this data immediately follows the instruction itself.
| Mnemonic Code | Assembled Code |
|---|---|
PLA |
$68 |
BEQ $03 |
$F0 $9F |
JMP $A5B6 |
$4C $B6 $A5 |
Key to Addressing modes:¶
| Implied | Accumulator | Immediate | Zero Page |
| - | A | # | 0 |
| Absolute | Indirect | X-indexed | Y-indexed |
| / | > | X | Y |
Note
The Cyborg Systems docs featured an incomplete table, so this is currently ommitted from these docs until a nice way to fit them into readthedocs is figured out.
The wikipedia table can be used in the meantime.