uvm/include/cpu.h

//   This file is part of uVM.
//
//   uVM 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.
//
//   uVM 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 uVM.  If not, see <http://www.gnu.org/licenses/>.
//

#include <vector>

#ifndef CPU_H_
#define CPU_H_

// CPU is a wrapper around our representation of a virtual CPU.
class CPU {
  private:
    int sp = -1;            // Stack pointer
    int ip = 0;             // Instruction pointer
    int fp;                 // Frame pointer
    std::vector<int> code;  // Our code in memory

    int *stack = NULL;


  // XXX: FIND A C++ TEST FRAMEWORK OMG LOL
  public:
    enum opcode {
      IPUSH  = 0x0,
      ISAVE0 = 0x1,
      ISAVE1 = 0x2,
      ISAVE2 = 0x3,
      ILOAD0 = 0x4,
      ILOAD1 = 0x5,
      ILOAD2 = 0x6,
      CMP    = 0x7,
      IADD   = 0x8,
      ISUB   = 0x9,
      JMP    = 0xA,
      JC     = 0xB,
      HALT   = 0xC,
      PRINT  = 0xD,
      IMUL   = 0xE,
      CALL   = 0xF,   // XXX: IMPLEMENT
      IDIV   = 0x10,
      IREM   = 0x11,
   };

    // Temporary registers
    int t0;
    int t1;
    int t2;

    // Comparison flag register
    int cf;

    const char* opcode_map[18] = {
      "IPUSH",
      "ISAVE0",
      "ISAVE1",
      "ISAVE2",
      "ILOAD0",
      "ILOAD1",
      "ILOAD2",
      "CMP",
      "IADD",
      "ISUB",
      "JMP",
      "JC",
      "HALT",
      "PRINT",
      "IMUL",
      "CALL",
      "IDIV",
      "IREM",
    };

    CPU(unsigned int);
    ~CPU();
    bool load(std::vector<int> code);
    void run();
};

#endif  // CPU_H_