public byte ReadByte(uint address)
{
if (address == 0x00100001)
{
ArmSimFormRef.WriteCharToTerminal("Hello World!");
return(0);
}
return(RAM[address]);
}
public bool execute()
{
// add address, instruction, and disassembled instruction strings to each list
string addr = "0x" + currentInstAddress.ToString("X").PadLeft(8, '0');
string inst = currentInstruction.ToString("x").PadLeft(8, '0');
#region For testing purposes
instAddressLst.Add(addr);
instLst.Add(inst);
#endregion
// prepare string
disassembledCombinedString = disassembledCombinedString + "\r\n" + addr + "\t" + inst + "\t";
lastDisString = disassembledCombinedString;
// will be used to collect strings to later concatenate with field string disassembledCombinedString
string tempStr = "";
// INJECT A NOP into execute if instruction is a NOP
if (Extras.isNOPInstruction(currentInstruction, registers.getNFlag(), registers.getZFlag(), registers.getCFlag(), registers.getVFlag()))
{
writeInfoToTraceLogForSimI();
#region For testing purposes
instDisLst.Add("NOP");
#endregion
disassembledCombinedString += "NOP";
lastDisString += "NOP";
return(false);
}
/************************SPECIAL CASES ****************************/
// SWI
if (Extras.isSWIInstruction(currentInstruction))
{
//Debug.WriteLine("SWI in CPU.decode(). End of instructions");
uint swi_imm = currentInstruction & 0x00ffffff;
// add swi immediate to disassembled list
tempStr = "svc 0x" + swi_imm.ToString("x").PadLeft(8, '0');
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
writeInfoToTraceLogForSimI();
switch (swi_imm.ToString("x").PadLeft(2, '0'))
{
case "00":
ArmSimFormRef.WriteCharToTerminal("Hello World!");
break;
case "11":
return(true);
case "6a":
while (!ArmSimFormRef.checkCharsQueueContainsReturn())
{
Thread.Sleep(2000);
}
bool gotReturnValue = false;
uint memoryBufferPlace = 0;
while (!gotReturnValue)
{
char readValue = ArmSimFormRef.dequeCharsQueue();
if (readValue == (char)13)
{
gotReturnValue = true;
if (memoryBufferPlace < registers.getRegNValue(2))
{
memory.WriteByte(registers.getRegNValue(1) + memoryBufferPlace, 0x0);
}
else
{
memory.WriteByte(registers.getRegNValue(1) + (memoryBufferPlace - 1), 0x0);
}
}
if (memoryBufferPlace < registers.getRegNValue(2))
{
Console.WriteLine(readValue);
memory.WriteByte(registers.getRegNValue(1) + memoryBufferPlace, Convert.ToByte(readValue));
memoryBufferPlace++;
}
}
//memory.WriteByte(registers.getRegNValue(1), 0x35);
//memory.WriteByte(registers.getRegNValue(1) + 1, 0x0);
break;
default:
break;
}
return(false); // true to stop executing more instructions
}
// MUL
if (Extras.isMulInstruction(currentInstruction))
{
mul_instruct.executeMul();
tempStr = mul_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
writeInfoToTraceLogForSimI();
return(false); // false to keep excuting more instructions
}
// BX CASE
if (Extras.isBX(currentInstruction))
{
bx_instruct.executeBx();
tempStr = bx_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
writeInfoToTraceLogForSimI();
return(false); // false to keep excuting more instructions
}
/************************NORMAL CASES ****************************/
// execute the instruction according to its type
switch (currentInstructionType)
{
case 0: // if Data Processing (00x)
case 1: // if Data Processing (00x)
data_processing_instruct.executeDP();
tempStr = data_processing_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
break;
case 2: // if Load/Store (01x)
case 3: // if Load/Store (01x)
load_store_instruct.executeLaS();
tempStr = load_store_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
break;
case 4: // if Load/Store (100) Load/Store Multiple FD variant
load_store_mul_instruct.executeLaSMul();
tempStr = load_store_mul_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
break;
case 5: // if Branch (101)
branch_instruct.executeB();
tempStr = branch_instruct.getInstructionString();
#region For testing purposes
instDisLst.Add(tempStr);
#endregion
disassembledCombinedString += tempStr;
lastDisString += tempStr;
break;
// TODO: Check special cases
default:
Debug.WriteLine("ERROR in CPU.execute(): Type is Special or Non-valid instruction.");
break;
} // end switch
writeInfoToTraceLogForSimI();
//Thread.Sleep(5000);
return(false);
}