uvm/src/uvm.cc

//   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>

#include "../include/cpu.h"

int main(int argc, char* argv[]) {
  // Allocate an 800 word stack size to the CPU on initialization
  CPU c(800);

  // XXX:
  // Until I find a unit testing framework these vectors of bytecode will
  // serve as (terrible) tests.

  // Answer: 3
  std::vector<int> code_iadd {
    CPU::opcode::IPUSH, 0x1,
    CPU::opcode::IPUSH, 0x2,
    CPU::opcode::IADD,
    CPU::opcode::PRINT,
    CPU::opcode::HALT
  };

  // Answer: 1
  std::vector<int> code_isub {
    CPU::opcode::IPUSH, 0x1,
    CPU::opcode::IPUSH, 0x2,
    CPU::opcode::ISUB,
    CPU::opcode::PRINT,
    CPU::opcode::HALT
  };

  // Answer: 16
  std::vector<int> code_imul {
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IMUL,
    CPU::opcode::PRINT,
    CPU::opcode::HALT,
  };

  // Answer: 1
  std::vector<int> code_idiv {
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IDIV,
    CPU::opcode::PRINT,
    CPU::opcode::HALT,
  };


  // Answer: 3 % 4 = 3 (0 remainder 3)
  std::vector<int> code_irem {
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IPUSH, 0x3,
    CPU::opcode::IREM,
    CPU::opcode::PRINT,
    CPU::opcode::HALT,
  };

  // Answer: 8
  // This tests unconditional jumping. If the JMP instruction fails the code will fail to
  // answer correctly.
  std::vector<int> code_jmp {
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::IPUSH, 0x4,
    CPU::opcode::JMP, 0x7,        // JMP to 0x7 - the 8th line of code in memory
    CPU::opcode::ISUB,
    CPU::opcode::IADD,
    CPU::opcode::PRINT,
    CPU::opcode::HALT,
  };

  // Answer: 10
  // This tests the use of conditional jumps to implement a simple while loop.
  std::vector<int> code_jc {
    CPU::opcode::IPUSH, 0xA,      // Limit
    CPU::opcode::ISAVE1,          // Store the limit
    CPU::opcode::IPUSH, 0x0,      // Counter
    CPU::opcode::ISAVE2,          // Store the counter
    CPU::opcode::IPUSH, 0x0,      // Accumulator (for our print)
    CPU::opcode::ISAVE0,          // Store the accumulator
    CPU::opcode::ILOAD1,          // Load the limit
    CPU::opcode::ILOAD2,          // Load the counter
    CPU::opcode::CMP,             // Compare limit to counter
    CPU::opcode::JC, 0x1A,        // Jump to PRINT if true
    CPU::opcode::ILOAD0,          // Load the accumulator
    CPU::opcode::IPUSH, 0x1,      // Push 1 onto the stack to be added to the accumulator
    CPU::opcode::IADD,            // Add 1 to the accumulator
    CPU::opcode::ISAVE0,          // Take the top of the stack, store it in t0 and pop it off
    CPU::opcode::ILOAD2,          // Reload the counter
    CPU::opcode::IPUSH, 0x1,      // Push 1 onto the stack to be added to the counter
    CPU::opcode::IADD,            // Add one to the accumulator
    CPU::opcode::ISAVE2,          // Store the counter
    CPU::opcode::JMP, 0x9,        // Jump to the CMP statement
    CPU::opcode::ILOAD0,          // Load the accumulator for PRINT
    CPU::opcode::PRINT,
    CPU::opcode::HALT,
  };

  c.load(code_jc);
  c.run();

  return 0;
}