main.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <optional>
#include <stdexcept>
#include <limits>
#include "cpu.hpp"
#include "parse_program.hpp"

std::optional<std::string> read_program_file(const std::string& filepath);
void initialize_memory(CPU& cpu, int argc, char* argv[]);

int main(int argc, char* argv[]) {
    if (argc < 2) {
        std::cerr << "usage: " << argv[0] << " <PROGRAM_FILE_PATH> [memory values]" << std::endl;
        return 1;
    }

    auto program_text = read_program_file(argv[1]);

    if (!program_text) {
        return 1;
    }

    try {
        CPU cpu;

        initialize_memory(cpu, argc, argv);

        cpu.instructions = parse_program(*program_text);
        cpu.run();

    } catch (const std::exception& e) {
        std::cerr << "error: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}

std::optional<std::string> read_program_file(const std::string& filepath) {
    std::ifstream file(filepath);
    if (!file) {
        std::cerr << "error: could not open file " << filepath << std::endl;
        return std::nullopt;
    }
    return std::string((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());
}

void initialize_memory(CPU& cpu, int argc, char* argv[]) {
    for (int i = 2; i < argc; ++i) {
        int memory_index = i - 2;
        uint64_t value;

        try {
            value = std::stoull(argv[i]); 
        } catch (...) {
            throw std::runtime_error("invalid memory value: " + std::string(argv[i]));
        }

        if (value > std::numeric_limits<uint32_t>::max()) {
            throw std::runtime_error("specified memory value out of range");
        }

        cpu.memory[memory_index] = static_cast<uint32_t>(value);
    }
}