3c_disasm/instr/branch.cpp

   1 #include "../Iinstr.hpp"
   2
   3 class Cbranch : public Iinstr {
   4         private:
   5                 bool m_taken;
   6                 char m_typ;
   7         public:
   8                 Cbranch();
   9                 void evalInstr();
  10                 void execInstr();
  11                 std::string toString();
  12 };
  13
  14 /**
  15  * Name:      create_instruction
  16  * Purpose:   if compiled as shared library, this functions creates the
  17               instruction object
  18
  19  * Returns:   pointer to instruction object
  20  */
  21 extern "C" Iinstr* create_instruction() {
  22     return new Cbranch();
  23 }
  24
  25 /**
  26  * Name:      destroy_instruction
  27  * Purpose:   if compiled as shared library, this functions destoys the
  28               instruction object
  29
  30  * Parameter: IInstruction - the instruction object to delete
  31  */
  32 extern "C" void destroy_instruction(Iinstr* p) {
  33     delete p;
  34 }
  35
  36 Cbranch::Cbranch() : m_taken(1), m_typ(0)
  37 {
  38         opcode = B5(10110);
  39         name = "branch";
  40 }
  41
  42 void Cbranch::evalInstr()
  43 {
  44         this->m_s = argbits[0];
  45         this->m_taken = argbits[1];
  46
  47         argbits >>= 2;
  48
  49         dynamic_bitset<> type = argbits;
  50         type.resize(2);
  51         this->m_typ = type.to_ulong();
  52
  53         switch(m_typ) {
  54                 case 0:
  55                         this->name = "branch";
  56                         break;
  57                 case 1:
  58                         this->name = "call";
  59                         break;
  60                 case 2:
  61                         this->name = "ret";
  62                         break;
  63                 case 3:
  64                         this->name = "reti";
  65                         break;
  66                 default:
  67                         cerr << "What have you done? 2 bits that have more than 4 values?!" << endl;
  68         }
  69
  70         argbits >>= 5;
  71
  72         dynamic_bitset<> immb = argbits;
  73         immb.resize(16);
  74         this->m_imm = this->generate16ImmSign(immb.to_ulong());
  75
  76 }
  77
  78 void Cbranch::execInstr()
  79 {
  80         cout << "should exec" << this->toString() << endl;
  81 }
  82
  83 std::string Cbranch::toString()
  84 {
  85         stringstream op;
  86         op << this->getName();
  87
  88         if(m_s) op << 'S';
  89
  90         op << this->getConditionFlag() << (m_taken ? '+' : '-');
  91         if(m_typ < 2) {
  92                 op << " 0x" << std::hex << m_imm << "(" << std::dec << m_imm << ")";
  93         }
  94         return op.str();
  95 }