Data registers are denoted D0, D1, D2, D3, D4, D5, D6, D7, and the address registers A0, A1, A2, A3, A4, A5, A6, A7. The contents of a register is denoted (D2), or [D2].
The first 8 bits of D2 is denoted D2[7:0].
The status register is SR, with CCR the condition code register.
The program counter is PC, and SP=A7 denotes the stack pointer (and corresponds to SSP in supervisor mode, and USP in user mode). ((SP)) denotes the contents of the stack, addressed by (SP).
| hex | binary |
| 0 | 0000 |
| 1 | 0001 |
| 2 | 0010 |
| 3 | 0011 |
| 4 | 0100 |
| 5 | 0101 |
| 6 | 0110 |
| 7 | 0111 |
| 8 | 1000 |
| 9 | 1001 |
| A | 1010 |
| B | 1011 |
| C | 1100 |
| D | 1101 |
| E | 1110 |
| F | 1111 |
Bytes can be written in hex: 0110 1110 = 6E
Words are written: 0110 1110 0101 1001 = 6E59
Longwords are written: 6E59 C72A
To avoid confusion, correct syntax must be used:
0b01101110 = 0x6E59 (C style) or $6E59
ANU Engineering - ENGN3213