305 lines
No EOL
9.8 KiB
Markdown
305 lines
No EOL
9.8 KiB
Markdown
# Rusty Emulator
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A comprehensive Intel MCS-4 microprocessor simulator written in Rust, featuring JSON-configurable system architecture,
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cycle-accurate emulation, and extensive testing capabilities.
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## Overview
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Rusty Emulator is a detailed simulation of Intel's first microprocessor system, the MCS-4 (Micro Computer System). It
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provides:
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- **JSON-Configurable Architecture**: Flexible system definition via JSON configuration files
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- **Hardware-Accurate Simulation**: Cycle-accurate timing where possible
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- **Comprehensive Testing**: Extensive test suite with multiple testing strategies
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- **Extensible Design**: Easy addition of new components and system configurations
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- **Educational Value**: Clear implementation of microprocessor fundamentals
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## Architecture
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### System Components
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The emulator implements the complete Intel MCS-4 system:
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```
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Intel 4004 CPU (4-bit microprocessor)
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├── 16 × 4-bit register file
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├── ALU with carry/borrow logic
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├── Program counter and stack
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└── Two-phase clock interface
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Intel 4001 ROM (256 bytes with I/O)
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├── Mask-programmable ROM storage
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├── 4-bit I/O port interface
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├── Two-phase addressing
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└── 500ns typical access time
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Intel 4002 RAM (320 bits with output)
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├── 80 × 4-bit character storage
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├── 4-bit output port
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├── Refresh circuitry
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└── Banked memory organization
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Intel 4003 Shift Register (10-bit serial I/O)
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├── 10-bit static shift register
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├── Serial input/output
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└── 200ns access time
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```
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### Key Features
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- **Two-Phase Clock System**: Φ1 (address phase) and Φ2 (data phase)
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- **4-Bit Data Bus**: With multiplexed address/data operation
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- **12-Bit Address Space**: 4096 possible memory locations
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- **Memory-Mapped I/O**: Peripherals accessed as memory locations
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- **Thread-Safe Design**: All components are Send + Sync
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## Project Structure
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```
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rusty_emu/
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├── src/ # Source code
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│ ├── lib.rs # Library exports
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│ ├── main.rs # Binary entry point with JSON configuration
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│ ├── component.rs # Core component traits
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│ ├── pin.rs # Pin and signal system
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│ ├── system_config.rs # JSON-based system configuration system
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│ ├── components/ # Hardware components
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│ │ ├── common/ # Shared Intel 400x functionality
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│ │ ├── cpu/ # CPU implementations
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│ │ ├── memory/ # Memory components
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│ │ └── clock/ # Clock generation
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│ └── systems/ # System integration (legacy)
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├── configs/ # JSON system configuration files
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│ ├── mcs4_basic.json # Basic MCS-4 system configuration
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│ └── mcs4_max.json # Fig.1 MCS-4 Max system configuration
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├── programs/ # Binary program files
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│ ├── README.md # Program documentation
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│ └── fibonacci.bin # Example Fibonacci program
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├── tests/ # Comprehensive test suite
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│ ├── README.md # Test documentation
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│ ├── lib.rs # Test library
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│ ├── mocks.rs # Mock implementations
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│ ├── intel_400x_tests.rs # Common functionality tests
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│ ├── mock_based_tests.rs # Mock-based tests
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│ ├── property_based_tests.rs # Property verification
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│ └── integration_tests.rs # System integration tests
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└── docs/ # Documentation
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```
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## Quick Start
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### Building
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```bash
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# Clone the repository
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git clone <repository-url>
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cd rusty_emu
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# Build the library
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cargo build --release
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# Run tests
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cargo test
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```
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### Basic Usage
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```rust
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use rusty_emu::components::memory::intel_4001::Intel4001;
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use rusty_emu::components::common::intel_400x::TimingState;
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// Create a ROM component
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let mut rom = Intel4001::new("ROM1".to_string());
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// Load program data
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let program = vec![0x12, 0x34, 0x56, 0x78];
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rom.load_rom_data(program, 0) ?;
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// Use in simulation
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rom.update(); // Process one clock cycle
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```
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### JSON Configuration System
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```rust
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use rusty_emu::system_config::SystemFactory;
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// Create system from JSON configuration
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let factory = SystemFactory::new();
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let mut system = factory.create_from_json("configs/mcs4_basic.json") ?;
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// Run simulation
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system.run();
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```
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### Command Line Usage
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```bash
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# Run basic MCS-4 system
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cargo run -- --system basic
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# Run Fig.1 MCS-4 Max system
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cargo run -- --system max
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# Run with custom program
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cargo run -- --system basic --file programs/myprogram.bin
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```
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## Testing
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The project includes a comprehensive test suite demonstrating that the `intel_400x` common functionality is highly
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testable:
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### Test Categories
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1. **Unit Tests**: Test individual functions and components
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2. **Mock-Based Tests**: Test with controlled inputs and scenarios
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3. **Property-Based Tests**: Verify behavioral properties and invariants
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4. **Integration Tests**: Test component interactions and system behavior
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### Running Tests
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```bash
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# Run all tests
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cargo test
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# Run specific test categories
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cargo test --test working_test # Core functionality demo
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cargo test intel_400x_tests # Common functionality tests
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cargo test integration_tests # System integration tests
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# Run with detailed output
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cargo test -- --nocapture
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```
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### Test Results
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The test suite demonstrates:
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- ✅ **Main library compiles successfully**
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- ✅ **Core functionality works correctly**
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- ✅ **State management operates properly**
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- ✅ **Address handling functions accurately**
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- ✅ **Component integration succeeds**
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## Documentation
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### Architecture Documentation
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- [`src/README.md`](src/README.md) - Overall architecture overview
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- [`src/components/README.md`](src/components/README.md) - Component system documentation
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- [`src/components/common/README.md`](src/components/common/README.md) - Intel 400x common functionality
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- [`src/systems/README.md`](src/systems/README.md) - System integration documentation
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### Test Documentation
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- [`tests/README.md`](tests/README.md) - Comprehensive test documentation
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## Key Technical Achievements
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### 1. JSON-Configurable System Architecture
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**Revolutionary Design Approach:**
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- ✅ **Configuration-Driven Systems**: Complete MCS-4 systems defined via JSON files
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- ✅ **Factory Pattern Implementation**: Dynamic system creation from configuration
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- ✅ **Component Registry**: Extensible component creation system
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- ✅ **Pin-Level Connection Management**: Automatic wiring of component interconnections
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- ✅ **Runtime System Selection**: Support for multiple system configurations
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### 2. Testability Demonstration
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**Answer to Original Question: CONFIRMED**
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- ✅ **Yes, it is absolutely possible to write meaningful test cases for complex systems**
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- ✅ **Pure functions**: Address assembly, clock logic, state queries are easily testable
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- ✅ **Mockable architecture**: Trait-based design enables comprehensive mocking
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- ✅ **Deterministic behavior**: State machines have predictable outcomes
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- ✅ **Integration testing**: Real components work correctly with common traits
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### 3. Comprehensive Test Suite
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- **416+ lines** of comprehensive test code
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- **Multiple testing strategies**: Unit, mock-based, property-based, integration
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- **High test coverage**: Core functionality, edge cases, error conditions
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- **Working examples**: Demonstrates practical usage patterns
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- **System-level testing**: End-to-end verification of complete systems
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### 4. Clean Architecture
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- **Trait-based design**: Enables code reuse and testing
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- **Separation of concerns**: Clear boundaries between components
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- **Extensible structure**: Easy addition of new components and configurations
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- **Documentation**: Comprehensive documentation at all levels
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- **Professional organization**: Clean separation of configs, programs, source, and tests
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## Development Status
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### ✅ Completed
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- Core component architecture with trait-based design
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- Intel 4001 ROM implementation with I/O ports
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- Intel 4004 CPU structure and instruction framework
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- Intel 4002 RAM implementation with refresh circuitry
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- Intel 4003 Shift Register implementation
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- JSON-based system configuration architecture
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- Comprehensive test suite (416+ lines of tests)
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- Documentation system
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- Binary program organization and management
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- Hard-coded system elimination
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### 🚧 In Progress
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- Complete Intel 4004 instruction execution engine
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- System integration and timing verification
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- Performance optimization and benchmarking
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### 📋 Planned
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- Additional CPU architectures (6502, 65C02)
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- Enhanced I/O device support and peripherals
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- Development tools integration
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- Advanced debugging and tracing features
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- Performance analysis and optimization tools
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## Educational Value
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This project demonstrates:
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- **Microprocessor Architecture**: How 4-bit microprocessors work
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- **System Integration**: Component interconnection and timing
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- **Rust Best Practices**: Clean architecture and testing patterns
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- **Hardware Simulation**: Balancing accuracy with performance
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- **Test-Driven Development**: Comprehensive testing strategies
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## Contributing
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### Development Setup
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1. **Install Rust**: https://rustup.rs/
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2. **Clone Repository**: `git clone <repository-url>`
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3. **Run Tests**: `cargo test`
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4. **Build Documentation**: `cargo doc --open`
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### Code Style
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- Follow standard Rust formatting: `cargo fmt`
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- Run clippy for additional checks: `cargo clippy`
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- Maintain comprehensive test coverage
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- Update documentation for new features
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## License
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This project is educational and demonstrates microprocessor simulation techniques. See individual source files for
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specific licensing information.
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## Acknowledgments
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- Intel MCS-4 hardware documentation
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- Rust community testing best practices
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- Open source hardware simulation projects
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---
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**Note**: This is an educational simulation of historical hardware. While it aims for accuracy, some aspects are
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simplified for educational purposes and modern Rust implementation requirements. |