Fixing Magic‐1 Emulator CPU Implementation Issues - retrotruestory/M1DEV GitHub Wiki

Collecting workspace information# Fixing Magic-1 Emulator CPU Implementation Issues

Looking at the error messages, there's a significant mismatch between the CPU class declaration in the header file and its implementation in the cpp file. The implementation contains many methods and member variables that aren't declared in the header.

The Problem

The cpu.cpp file is trying to use:

1. Member variables that don't exist in the class declaration (microcodePC, CSR)
2. Register fields that aren't defined (MDR, MAR, Z, N, etc.)
3. Bus structures and methods that aren't declared

Solution Approach

We need to align the header and implementation by either adding the missing declarations to the header or modifying the implementation to match the header.

Let's first fix the most critical issues in cpu.cpp:

// Look at the constructor issues first
CPU::CPU(Memory& mem) :
    memory(mem),
    state(State::RESET),
    cycleCount(0),
    // Remove microcodePC from here
    registers(),  // Initialize the registers structure
    breakpoints(),
    // Remove CSR from here
    traceEnabled(false),
    deviceData(0)
{
    reset();
}

// Fix the reset method - replace with what's in the header
void CPU::reset() {
    // Set initial register values
    registers = {}; // Reset all registers to zero
    registers.PC = 0;
    registers.SP = 0xF000; // Default stack pointer
    registers.MSW = 0x80;  // Supervisor mode enabled
    
    // Clear state variables
    state = State::RUNNING;
    cycleCount = 0;
    pendingInterrupts = 0;
    
    // Clear any breakpoints
    breakpoints.clear();
    watchpoints.clear();
}

// Add the missing implementation for disassembleInstruction
std::string CPU::disassembleInstruction(Word instruction) const {
    std::ostringstream oss;
    
    // Extract the opcode and operand
    Word opcode = (instruction >> 8) & 0xFF;
    Word operand = instruction & 0xFF;
    
    // Disassemble based on the Magic-1 instruction set
    switch (opcode) {
        // System Operations
        case 0x00: oss << "NOP"; break;
        case 0x01: oss << "HALT"; break;
        case 0x02: oss << "SYSCALL #" << std::dec << operand; break;
        case 0x03: oss << "TRAPO"; break;
        case 0x04: oss << "BPT"; break;
        case 0x05: oss << "RETI"; break;
        
        // Many more cases would go here...
        
        default:
            oss << "UNKNOWN " << std::hex << std::uppercase << std::setw(2) << opcode 
                << " " << std::setw(2) << operand;
            break;
    }
    
    return oss.str(); // Return the disassembled instruction
}

Next Steps

After fixing these immediate issues, we'll need to address:

1. The cpu.h file to add missing declarations
2. device.cpp to remove duplicate definitions
3. system.cpp issues

The CPU implementation is complex with microcode-level simulation. I recommend:

1. First fixing disassembleInstruction() to get past the immediate error
2. Then creating a plan to align your header and implementation
3. Finally fixing the duplicate function definitions in device.cpp

Would you like me to provide more specific guidance on any of these steps?