public static String readStringFromHeap(Stack data, Heap heap)
{
// get address
int addr = data.popInt();
int ptr = data.readInt((int)data.Position + addr * sizeof(int));
return heap.readString(ptr);
}
/// <summary>
/// Executes a subroutine. All parameters must be written to the heap before execution.
/// Afterwards the addresses of the parameters have to be stored in the stack (realtive to stackpointer).
/// Mind this if you want to execute a script with external parameters.
/// </summary>
/// <param name="programCode">The script's code.</param>
/// <param name="data">The data stack of the current script execution.</param>
public void executeSub(MemoryStream programCode, int entryPoint, Stack data, Heap heap)
{
m_eip = entryPoint;
m_ebp = (int)data.Position; // base pointer
readNextOpCode(programCode);
while (m_opcode != OpCode.HALT)
{
//eip = (int)programCode.Position;
switch (m_opcode)
{
case OpCode.POP_INT:
{
break;
}
case OpCode.POP_FLOAT:
{
break;
}
case OpCode.POP_STRING:
{
break;
}
case OpCode.PUSH_INT:
{
data.push(readNextProgramInt(programCode));
break;
}
case OpCode.PUSH_FLOAT:
{
data.push(readNextProgramFloat(programCode));
break;
}
case OpCode.PUSH_STRING:
{
data.push(readNextProgramString(programCode));
break;
}
case OpCode.PUSH_ADDR:
{
int addr = readNextProgramInt(programCode); // address relative to ebp
// read heap address from stack
int heapAddr = data.readInt(m_ebp + addr);
data.push(heapAddr);
break;
}
case OpCode.PUSH_EBP:
{
data.push(m_ebp);
break;
}
case OpCode.ADD_INT:
{
int val1 = data.popInt();
int val2 = data.popInt();
data.push(val1 + val2);
break;
}
case OpCode.SUB_INT:
{
int val1 = data.popInt();
int val2 = data.popInt();
data.push(val1 - val2);
break;
}
case OpCode.READ_INT:
{
int addr = data.popInt();
data.push(data.readInt(addr));
break;
}
case OpCode.WRITE_INT:
{
// read address
int addr = data.popInt();
// read value
int value = data.popInt();
// write
data.writeInt(addr,value);
break;
}
case OpCode.READ_FLOAT:
{
int addr = data.popInt();
data.push(data.readFlt(addr));
break;
}
case OpCode.WRITE_FLOAT:
{
// read address
int addr = data.popInt();
// read value
float value = data.popInt();
// write
data.writeFlt(addr, value);
break;
}
case OpCode.ALLOC_STRING_ON_HEAP:
{
String s = data.popString();
int address = heap.allocString(s);
data.push(address);
break;
}
case OpCode.READ_STRING_FROM_HEAP:
{
//int ptr = data.readInt((int)data.Position + addr * sizeof(int));
int ptr = data.popInt();
String s = heap.readString(ptr);
data.push(s);
break;
}
case OpCode.BEGIN_BLOCK:
{
// save base pointer
m_ebp = (int)data.Position;
data.push(m_ebp);
break;
}
case OpCode.CALL_FUNCTION:
{
// get function address
int func_addr = data.popInt();
// save instruction pointer
data.push(m_eip);
m_eip = func_addr;
programCode.Position = m_eip;
break;
}
case OpCode.RETURN:
{
m_eip = data.popInt(); // restore eip
programCode.Position = m_eip;
break;
}
case OpCode.END_BLOCK:
{
m_ebp = data.popInt(); // restore ebp
data.set(m_ebp);
break;
}
// Built in function
case OpCode.NATIVE_CALL:
{
int f = readNextProgramInt(programCode);
if (f > 0)
{
m_registeredFunctions.RegisteredFunctionAddresses[f].execute(data,heap);
}
else if (f < 0)
{
m_registeredFunctions.RegisteredFunctionAddresses[-1*f].end(data,heap);
}
break;
}
}
readNextOpCode(programCode);
}
}