Magic-1 Computer Architecture Layers

1. Hardware Layer

CPU Core

• 16-bit data path
• Two-bus architecture (L-bus and R-bus)
• Hardware memory management
• Microcode control unit

Core Components:
└── CPU
    ├── ALU (16-bit)
    ├── Register File
    │   ├── MSW (Machine Status Word)
    │   ├── PC (Program Counter)
    │   ├── SP (Stack Pointer)
    │   ├── A, B (General Purpose)
    │   ├── C (General Purpose)
    │   └── MDR (Memory Data Register)
    ├── Memory Management Unit
    │   ├── Page Tables
    │   └── Address Translation
    └── Control Unit
        ├── Microcode ROM
        └── Instruction Decoder

2. Microcode Layer

Control Structure (56-bit microinstruction)

typedef struct {
    unsigned next:8;        // Next address
    unsigned latch:4;       // Register control
    unsigned mar_latch:1;   // MAR control
    unsigned mdr_ctrl:2;    // MDR control
    unsigned priv:1;        // Privilege level
    unsigned mode:2;        // Operating mode
    unsigned bus_ctrl:6;    // Bus control
    unsigned alu_op:4;      // ALU operation
    unsigned misc:28;       // Misc control
} microinstruction_t;

3. Instruction Set Layer

Instruction Categories

Instructions:
├── Data Movement
│   ├── LD/ST (Load/Store)
│   └── PUSH/POP
├── ALU Operations
│   ├── ADD/SUB
│   ├── AND/OR/XOR
│   └── Shift/Rotate
├── Control Flow
│   ├── BR (Branch)
│   ├── CALL/RET
│   └── RETI
└── System Operations
    ├── CLI/STI
    ├── HALT
    └── Page Table Management

4. Operating System Layer

Memory Organization

Address Space:
0x0000-0x3FFF: ROM (16KB)
0x4000-0x7FFF: Device SRAM (16KB)
0x8000-0xF7FF: Main Memory
0xF800-0xFFFF: Device Page

Device Interface

I/O Devices:
├── UART (2x)
├── RTC
├── IDE Controller
├── CF Card Interface
└── Front Panel

5. Boot Process Layer

Initialization Sequence

1. ROM Boot
2. Hardware Initialize
3. Storage Detection
4. Boot Image Load
5. Memory Setup
6. Transfer Control

6. Application Layer

Program Environment

User Space:
├── Code Segment
├── Data Segment
├── Stack
└── I/O Access
    └── System Calls

All layers are accessible through VS Code's integrated development environment, with debugging and testing support for each level.