3c_disasm/instr/branchreg.cpp

   1 #include "../Iinstr.hpp"
   2
   3 class Cbranchreg : public Iinstr {
   4         private:
   5                 bool m_taken;
   6                 char m_typ;
   7         public:
   8                 Cbranchreg();
   9                 void evalInstr();
  10                 void execInstr();
  11                 std::string toString();
  12                 Iinstr* getNew();
  13 };
  14
  15 /**
  16  * Name:      create_instruction
  17  * Purpose:   if compiled as shared library, this functions creates the
  18               instruction object
  19
  20  * Returns:   pointer to instruction object
  21  */
  22 extern "C" Iinstr* create_instruction() {
  23     return new Cbranchreg();
  24 }
  25
  26 Iinstr* Cbranchreg::getNew()
  27 {
  28         return new Cbranchreg();
  29 }
  30 /**
  31  * Name:      destroy_instruction
  32  * Purpose:   if compiled as shared library, this functions destoys the
  33               instruction object
  34
  35  * Parameter: IInstruction - the instruction object to delete
  36  */
  37 extern "C" void destroy_instruction(Iinstr* p) {
  38     delete p;
  39 }
  40
  41 Cbranchreg::Cbranchreg() : m_taken(1), m_typ(0)
  42 {
  43         opcode = B5(10111);
  44         name = "branchreg";
  45 }
  46
  47 void Cbranchreg::evalInstr()
  48 {
  49         argbits >>= 2;
  50
  51         dynamic_bitset<> type = argbits;
  52         type.resize(1);
  53         this->m_typ = type.to_ulong();
  54
  55         switch(this->m_typ) {
  56                 case 0:
  57                         this->name = "brr";
  58                         break;
  59                 case 1:
  60                         this->name = "callr";
  61                         break;
  62                 default:
  63                         cerr << "What have you done? 1 bits that have more than 2 values?!" << endl;
  64         }
  65
  66         argbits >>= 17;
  67         m_rd = this->getRegister(argbits);
  68 }
  69
  70 void Cbranchreg::execInstr()
  71 {
  72         //cout << "should exec " << this->toString() << endl;
  73         CDat pc = this->m_cpu->getRegister(this->m_rd);
  74         pc *= 4; //komisch fix?
  75
  76         if(this->m_typ == 1) {
  77                 CDat sp = this->m_cpu->getStack();
  78                 sp -= 4;
  79                 this->m_cpu->setRAM(sp, this->m_cpu->getNextPC());
  80                 this->m_cpu->setStack(sp);
  81         }
  82         this->m_cpu->setNextPC(pc);
  83 }
  84
  85 std::string Cbranchreg::toString()
  86 {
  87         stringstream op;
  88         op << this->getName();
  89
  90         op << this->getConditionFlag();
  91         op << " r" << m_rd;
  92         return op.str();
  93 }