ocpu
GRU ocpu - yet another cpu design
Features
- little endian
- 16-bit
Registers
| Register | Category | Description |
|---|---|---|
| AL | General | 0xA0, 8-bit |
| AH | General | 0xA1, 8-bit |
| A | General | 0x0A, 16-bit |
| BL | General | 0xB0, 8-bit |
| BH | General | 0xB1, 8-bit |
| B | General | 0x0B, 16-bit |
| CL | General | 0xC0, 8-bit |
| CH | General | 0xC1, 8-bit |
| C | General | 0x0C, 16-bit |
| DL | 0xD0, 8-bit | |
| DH | 0xD1, 8-bit | |
| D | 0x0D, 16-bit | |
| EL | 0xE0, 8-bit | |
| EH | 0xE1, 8-bit | |
| E | 0x0E, 16-bit | |
| FL | 0xF0, 8-bit | |
| FH | 0xF1, 8-bit | |
| F | 0x0F, 16-bit | |
| PC | Pointer | Program Counter, 16-bit |
| SP | Poiner | Stack Pointer, 16-bit |
| ZF | Flag | Zero Flag |
| NF | Flag | Negative Flag |
| CF | Flag | Carry Flag |
| OF | Flag | Overflow Flag |
Instuctions
| Instructions | Opcode | Description |
|---|---|---|
| MOV reg, imm16 | 0x01 | Place value to register. |
| MOV reg, reg | 0xA1 | Takes 2 bytes as arguments: |
| 1 - Opcode of register | ||
| 2 - Value or register | ||
| ADD reg, imm16 | 0x10 | Add |
| ADD reg, reg | 0xB0 | |
| ADC reg, imm16 | 0x11 | Add with carry |
| ADC reg, reg | 0xB1 | |
| SUB reg, imm16 | 0x12 | Subtract |
| SUB reg, reg | 0xB2 | |
| MUL reg, imm16 | 0x13 | Multiply |
| MUL reg, reg | 0xB3 | |
| DIV reg, imm16 | 0x14 | Divide |
| DIV reg, reg | 0xB4 | |
| INC reg | 0x15 | Increment |
| DEC reg | 0x16 | Decrement |
| AND | 0x20 | |
| OR | 0x21 | |
| NOR | 0x22 | |
| XOR | 0x23 | |
| NAND | 0x24 | |
| CMP reg, imm16, imm16 | 0x25 | Compare |
| CMP reg, reg, imm16 | 0xC5 | |
| CMP reg, reg, reg | ||
| PUSH imm16 | 0x30 | Push to stack |
| POP | 0x31 | Pop to stack |
| JMP imm16 | 0x40 | Jump |
| JSR imm16 | 0x41 | Jump to subroutine |
| JC imm16 | 0x42 | Jump with carry |
| JNC imm16 | 0x43 | Jump without carry |
| JZ imm16 | 0x44 | Jump if zero |
| JNZ imm16 | 0x45 | Jump if non-zero |
| JE imm16 | 0x46 | Jump if equal |
| JL imm16 | 0x47 | Jump if lower |
| JH imm16 | 0x48 | Jump if higher |
| RTS | 0x49 | Return from subroutine |
| INB imm16 | 0x50 | Copies value from I/O port to destination |
| OUTB imm16 | 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: add instructions for memory use
TODO: add instructions for setting flags
TODO: add more description