C++ HOMEWORK

#include <iostream> #include <iomanip> #include <fstream> #include <string> #include <sstream> #include "Assembler.h" using namespace std; Assembler::Assembler() { jumpTable["load"] = &Assembler::load; jumpTable["loadi"] = &Assembler::loadi; jumpTable["store"] = &Assembler::store; jumpTable["add"] = &Assembler::add; ... } // Assembler int Assembler::assemble(fstream& in, fstream& out) { string line; string opcode; const int success = false; const int error = true; //const int debug = false; int instruction; getline(in, line); while (!in.eof()) { istringstream str(line.c_str()); str >> opcode; if (opcode[0] == '!') { getline(in, line); continue; } try { if (not jumpTable[opcode] ) throw NullPointerException(); else instruction = (this->*jumpTable[opcode])(str); } catch (NullPointerException e) { cerr << e.what() << endl; return error; } if (instruction == -1) return error; out << instruction << endl; getline(in, line); } return success; } // assemble int Assembler::load(istringstream & str) { int rd, addr; str >> rd >> addr; if (rd < 0 || rd > 3) return -1; if (addr < 0 || addr > 255) return -1; int inst=0; inst = inst | rd<<9 | addr; return inst; } int Assembler::loadi(istringstream & str) { int rd, constant; str >> rd >> constant; if (rd < 0 || rd > 3) return -1; if (constant < -128 || constant > 127) return -1; int inst=0; inst = inst | rd<<9 | 1<<8 | (0x000000ff & constant); return inst; } int Assembler::store(istringstream & str) { int rd, addr; str >> rd >> addr; if (rd < 0 || rd > 3) return -1; if (addr < 0 || addr > 255) return -1; int inst=1; inst = inst<<11 | rd<<9 | addr; return inst; } int Assembler::add(istringstream & str) { int rd, rs; str >> rd >> rs; if (rd < 0 || rd > 3) return -1; if (rs < 0 || rs > 3) return -1; int inst=2; inst = inst<<11 | rd<<9 | rs<<6; return inst; } ...