/*
PlutoISA
Copyright (C) 2024  Patrick_Pluto

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#pragma once

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cstdint>

namespace plutoisa {
    using namespace std;

    uint8_t *registers = ( uint8_t * ) malloc ( 8 * sizeof ( uint8_t ) );
    uint8_t *memory = ( uint8_t * ) malloc ( 128 * sizeof ( uint8_t ) );
    uint8_t *pointer = ( uint8_t * ) malloc ( sizeof ( uint8_t ) );

    void cpuInstructions ( uint8_t *rom ) {
        cout << static_cast<int>(rom[*pointer]) << endl;
        cout << static_cast<int>(*pointer) << endl;
        switch ( rom[*pointer] ) {
        case 0x00: // GET
            registers[rom[*pointer + 1]] = rom[*pointer + 2];
            *pointer += 3;
            break;
        case 0x01: // LOAD
            registers[rom[*pointer + 1]] = memory[rom[*pointer + 2]];
            *pointer += 3;
            break;
        case 0x02: // STORE
            memory[rom[*pointer + 2]] = registers[rom[*pointer + 1]];
            *pointer += 3;
            break;
        case 0x03: // ADD
            registers[rom[*pointer + 1]] = registers[rom[*pointer + 2]] + registers[rom[*pointer + 3]];
            *pointer += 4;
            break;
        case 0x04: // SUB
            registers[rom[*pointer + 1]] = registers[rom[*pointer + 2]] - registers[rom[*pointer + 3]];
            *pointer += 4;
            break;
        case 0x05: // JMP
            *pointer = rom[*pointer + 1];
            break;
        case 0x06: // JEQ
            if ( rom[*pointer + 2] == registers[rom[*pointer + 3]] ) {
                *pointer = rom[*pointer + 1];
            }
            break;
        default:
            cout << "Invalid Instruction, quitting." << endl;
            exit ( 1 );
        }
    }

    void cpuEmulation ( uint8_t *rom ) {
        *pointer = 0;

        while ( true ) {
            cpuInstructions ( rom );
        }
    }
}