6.4 KiB
6.4 KiB
ocpu
GRU ocpu - yet another cpu design
Features
- little endian
- 8-bit (maybe will be changed in future)
Registers
| Register | Category | Description |
|---|---|---|
| A | General | 0x0A |
| B | General | 0x0B |
| C | General | 0x0C |
| D | 0x0D | |
| E | 0x0E | |
| F | 0x0F | |
| PC | Pointer | Program Counter |
| SP | Poiner | Stack Pointer |
| ZF | Flag | Zero Flag |
| NF | Flag | Negative Flag |
| CF | Flag | Carry Flag |
| OF | Flag | Overflow Flag |
Instuctions
| Instructions | Opcode | Description |
|---|---|---|
| MOV | 0x01 | Place value to register. |
| Takes 2 bytes as arguments: | ||
| 1 - Opcode of register | ||
| 2 - Value | ||
| ADD | 0x10 | |
| ADC | 0x11 | |
| SUB | 0x12 | |
| MUL | 0x13 | |
| DIV | 0x14 | |
| INC | 0x15 | Increment |
| DEC | 0x16 | Decrement |
| AND | 0x20 | |
| OR | 0x21 | |
| NOR | 0x22 | |
| XOR | 0x23 | |
| NAND | 0x24 | |
| CMP | 0x25 | Compare |
| PUSH | 0x30 | Push to stack |
| POP | 0x31 | Pop to stack |
| JMP | 0x40 | Jump |
| JSR | 0x41 | Jump to subroutine |
| JC | 0x42 | Jump with carry |
| JNC | 0x43 | Jump without carry |
| JZ | 0x44 | Jump if zero |
| JNZ | 0x45 | Jump if non-zero |
| JE | 0x46 | Jump if equal |
| JL | 0x47 | Jump if lower |
| JH | 0x48 | Jump if higher |
| RTS | 0x49 | Return from subroutine |
| INB | 0x50 | Copies value from I/O port to destination |
| OUTB | 0x51 | Copies value from operand to I/O port |
| NOP | 0x90 | No operation |
0x0* - MOV instructions (maybe it will for LDA or something)
0x1* - Arithmetic (ADD, SUB and others)
0x2* - Logic (AND, OR and others)
0x3* - Stack Operations (PUSH, POP)
0x4* - Jumps
0x5* - Ports Operations
0x90 - NOP
TODO: add interrupts
TODO: add HLT
TODO: make instructions for memory use