/// <summary>Assembles the given instruction line, writing the opcode to the right memory location</summary>
/// <param name="instruction">The whole instruction line</param>
public void assemble(string instruction)
{
ushort addr;
string opcode;
string operand;
#if MONO || !DOTNET2
string[] instr = split(instruction, ' ', 3);
#else
string[] instr = instruction.Split(new char[] { ' ' }, 3, StringSplitOptions.RemoveEmptyEntries);
#endif
addr = ushort.Parse(instr[0]);
opcode = instr[1];
operand = (instr.Length >= 3) ? instr[2] : null;
CpuInstruction operation = assembleInstruction(addr, opcode, operand);
if (echoAssembledInstructions)
{
Console.WriteLine("{0}:\t{1}", addr, operation.ToString());
}
// Write the instruction to the assembly core's RAM:
memory[addr] = operation[0];
memory[addr + 1] = operation[1];
}
/// <summary>Decodes and executes instructions</summary>
public unsafe bool execute()
{
while (!vm.psrH)
{
op = vm.getNextInstruction(); // Fetch & decode the next instruction to execute
// Display the monitor if requested
if (debug)
{
monitor();
}
// Increment our instruction counter
++ops;
#region Write trace data if necessary
if (saveTrace)
{
traceFile.WriteLine("\t\tPSR={0}, FP={1}, SP={2}, MP={3}", vm.PSR, vm.FP, vm.SP, vm.MP);
traceFile.Write("{0}\t{1}", (vm.PC - 2), op.ToString());
}
#endregion
#region Instruction Execution
switch ((OpCode)op.opcode)
{
case OpCode.NOOP: // "Do Nothing"
// Allow the monitor to reassert itself after the next noop
if (noopBreak)
{
debug = true;
}
break;
// MATHS OPERATIONS //
case OpCode.ADD:
vm.add(); break;
case OpCode.SUB:
vm.sub(); break;
case OpCode.DVD:
vm.div(); break;
case OpCode.MUL:
vm.mul(); break;
case OpCode.DREM:
vm.mod(); break;
case OpCode.INCR: // Increment the top of the stack by operand
vm.incr((short)op.operand);
break;
// LOGICAL OPERATIONS //
case OpCode.LOR:
vm.lor(); break;
case OpCode.INV:
vm.lnot(); break;
case OpCode.NEG:
vm.neg(); break;
case OpCode.LAND:
vm.land(); break;
case OpCode.SLL:
vm.lsl(op.operand); break;
case OpCode.SRL:
vm.lsr(op.operand); break;
// COMPARISONS //
case OpCode.CLT: // if (pop() < pop()) push(1) else push(0);
cmps++;
short clt2 = (short)vm.pop();
short clt1 = (short)vm.pop();
if (clt1 < clt2)
{
vm.push(1);
}
else
{
vm.push(0);
}
break;
case OpCode.CLE: // if (pop() <= pop()) push(1) else push(0);
cmps++;
short cle2 = (short)vm.pop();
short cle1 = (short)vm.pop();
if (cle1 <= cle2)
{
vm.push(1);
}
else
{
vm.push(0);
}
break;
case OpCode.CEQ: // if (pop() == pop()) push(1) else push(0);
cmps++;
if (vm.pop() == vm.pop())
{
vm.push(1);
}
else
{
vm.push(0);
}
break;
case OpCode.CNE: // if (pop() != pop()) push(1) else push(0);
cmps++;
if (vm.pop() != vm.pop())
{
vm.push(1);
}
else
{
vm.push(0);
}
break;
// BRANCHING //
case OpCode.BRN:
vm.PC = op.getOffsetOperand(); break;
case OpCode.BIDX:
ushort jumpIncrement = vm.pop();
ushort increments = op.operand;
ushort jumpWords = (ushort)(jumpIncrement * increments);
vm.PC += jumpWords;
break;
case OpCode.BZE: // Branch to m if pop() == 0
if (vm.pop() == 0)
{
vm.PC = op.getOffsetOperand();
}
break;
case OpCode.BNZ: // Branch to m if pop() != 0
if (vm.pop() != 0)
{
vm.PC = op.getOffsetOperand();
}
break;
case OpCode.BNG: // Branch to m if pop() < 0
if ((short)vm.pop() < 0)
{
vm.PC = op.getOffsetOperand();
}
break;
case OpCode.BPZ: // Branch to m if pop() >= 0
if ((short)vm.pop() >= 0)
{
vm.PC = op.getOffsetOperand();
}
break;
case OpCode.BVS: // unknown
if (vm.psrV)
{
vm.psrV = false; // Clear the flag
vm.PC = op.getOffsetOperand();
}
break;
case OpCode.BES: // unknown
if (vm.psrE)
{
vm.psrE = false; // Clear the flag
vm.PC = op.getOffsetOperand();
}
break;
// SUBROUTINES //
case OpCode.MARK: // Set MP to SP and increment SP by m
vm.MP = vm.SP;
vm.SP += op.operand;
break;
case OpCode.CALL: // Store FP and PC to the current frame; FP=MP; PC=m
#if SYSROUTINE_INT_HACK
// Hack around a bug in the spec: don't CALL the readInt and writeInt system routines (CALLing would corrupt the current frame)
ushort jumpTo = op.getOffsetOperand();
if (jumpTo == 50 || jumpTo == 100)
{
if (jumpTo == 50) // readInt
{
ioSinceMonitor = true;
bool valid = false;
while (!valid)
{
try {
string intinLine = Console.ReadLine();
short intin = (short)int.Parse(intinLine);
vm.push((ushort)intin);
if (ioLog)
{
if (ioLog)
{
ioFile.WriteLine(intin);
}
}
valid = true;
}
catch (FormatException) {
Console.WriteLine("(Invalid Number. Try again)");
}
}
}
else // writeInt
{
ioSinceMonitor = true;
short intout = (short)vm.pop();
Console.Write(intout);
if (ioLog)
{
ioFile.Write(intout);
}
break;
}
}
else // Normal CALL implementation
{
vm.memory[vm.MP + 1] = vm.FP;
vm.memory[vm.MP + 2] = vm.PC;
vm.FP = vm.MP;
vm.PC = jumpTo;
}
#else
vm.memory[vm.MP + 1] = vm.FP;
vm.memory[vm.MP + 2] = vm.PC;
vm.FP = vm.MP;
vm.PC = op.getOffsetOperand();
#endif
break;
case OpCode.EXIT: // Restore FP and PC from the MP stack
vm.SP = vm.FP;
vm.FP = vm.memory[vm.SP + 1];
vm.PC = vm.memory[vm.SP + 2]; // jump back to the caller
break;
// LOADING //
case OpCode.LOADL: // Load a value (operand)
vm.push(op.operand); break;
case OpCode.LOADR: // Load the value in a register
vm.push(vm.getRegister(op.register)); break;
case OpCode.LOAD: // Load the value of the offset operand
vm.push(vm.memory[op.getOffsetOperand()]); break;
case OpCode.LOADA: // Load the address of the offset operand
vm.push(op.getOffsetOperand()); break;
case OpCode.LOADI: { // Load (operand) words onto the stack, source address on the top of the stack
ushort src = vm.pop(); // get the src address
ushort srcMax = (ushort)(src + (op.operand));
for (; src < srcMax; src += 2)
{
vm.push(vm.memory[src]);
}
break;
}
// STORING //
case OpCode.STORER: // Pop to a register
vm.setRegister(op.register, vm.pop());
break;
case OpCode.STORE: // Pop, using m as the destination address
vm.memory[op.getOffsetOperand()] = vm.pop();
//vm.memSetWord(op.getOffsetOperand(), vm.pop());
break;
case OpCode.STOREI: { // Pop (operand) words from the stack
ushort dest = vm.pop();
for (int i = op.operand; i != 0; --i)
{
vm.memory[dest++] = vm.pop();
}
break;
}
case OpCode.STZ: // Store 0 to memory location m
vm.memory[op.getOffsetOperand()] = 0;
break;
case OpCode.INCREG: // Increment register by n
vm.incRegister(op.register, op.operand);
break;
case OpCode.MOVE: // Copy n words from (SP-2) to (SP-1)
ushort mdest = vm.pop();
ushort msrc = vm.pop();
vm.memCopyWord(msrc, mdest, op.operand);
break;
case OpCode.SETSP:
vm.SP = op.getOffsetOperand();
break;
case OpCode.SETPSR:
vm.PSR = op.operand;
break;
case OpCode.HALT: // Sets the HALT bit of the PSR
vm.psrH = true;
break;
// Check instruction:
case OpCode.CHECK:
vm.SP -= 2;
short check1 = (short)vm.memory[vm.SP];
short check2 = (short)vm.memory[vm.SP - 1];
short check3 = (short)vm.memory[vm.SP + 1];
if (check1 <= check2 && check2 <= check3)
{
vm.psrE = false;
}
else // If the PSR[C] bit is set, halt the CPU
{
vm.psrE = true;
vm.psrH = vm.psrC;
}
throw new NotImplementedException("CHECK instruction is not yet implemented in this virtual machine");
// Character reading and writing:
case OpCode.CHIN:
ioSinceMonitor = true;
int chinChar = Console.Read();
vm.push((ushort)chinChar); // Technically allows unicode
if (ioLog)
{
ioFile.Write(chinChar);
}
break;
case OpCode.CHOUT:
ioSinceMonitor = true;
char choutChar = (char)vm.pop();
Console.Write(choutChar); // Technically allows unicode
if (ioLog)
{
ioFile.Write(choutChar);
}
break;
////-------------- NON-STANDARD OPCODES FOLLOW! --------------////
#if !NOEXTENDEDINSTRUCTIONS
case OpCode.BLANK: // Do absolutely nothing (intended as an alternative to NOOP for VM debugging)
break;
#endif
default:
throw new ArgumentOutOfRangeException("Encountered invalid opcode: " + op.opcode);
} // end switch
#endregion // Instruction Execution
// If the CPU has been halted:
if (vm.psrH)
{
closeFiles();
Console.WriteLine("\n>VM: CPU HALTED");
// Run the monitor
if (haltBreak)
{
Console.WriteLine("<ENTERING MONITOR>");
monitor();
}
}
} // while(true)
return(!vm.psrH);
} // end tick()
/// <summary>A simple debugging console</summary>
public unsafe void monitor()
{
#region Monitor disappearance conditions
if (addrBreak != -1) // If we have been instructed to break at a specific address:
{
if (vm.PC - 2 != addrBreak)
{
return; // Do not display the monitor yet
}
else
{
addrBreak = -1;
}
}
else if (monitorSkipInstructions != 0)
{
if (--monitorSkipInstructions > 0)
{
return; // Do not display the monitor yet
}
}
#endregion
#region Handle coexistance with the UI nicely
// If the CPU has performed IO since the last execution, ensure we're on a new line
if (ioSinceMonitor)
{
Console.WriteLine();
ioSinceMonitor = false;
}
#endregion
// If the user requested it, automatically display the decode of the instruction
if (autoDecode)
{
Console.WriteLine("\t{1}", (vm.PC - 2), op.ToString());
}
// Keep accepting arguments until we receive a terminal command
#region Monitor switch
while (true)
{
Console.Write("[{0}] Monitor> ", (vm.PC - 2));
string[] cmds = TargetVM.std.ArgParser.parse(Console.ReadLine());
if (cmds.Length == 0)
{
return;
}
switch (cmds[0].ToLower())
{
case null:
case "":
case "c":
case "continue":
return;
case "next":
case "n":
debug = true;
return;
case "r":
case "run":
debug = false;
return;
case "k":
case "skip": // Skip n executions:
if (cmds.Length == 2)
{
monitorSkipInstructions = parseAddr(cmds[1]);
Console.WriteLine("Skipping monitor for next {0} instruction(s).", monitorSkipInstructions);
return;
}
else
{
Console.WriteLine("Target Monitor: skip requires an argument. Example: skip 5");
break;
}
case "b":
case "break": // Break at a specific address
if (cmds.Length == 2)
{
addrBreak = parseAddr(cmds[1]);
Console.WriteLine("Setting breakpoint at address {0}.", addrBreak);
return;
}
else
{
Console.WriteLine("Target Monitor: break requires an argument. Example: break 210");
break;
}
case "s":
case "halt":
case "stop":
case "exit":
case "quit":
case "q": // halt execution and terminate
closeFiles();
Console.WriteLine("Target Monitor: goodbye.");
System.Environment.Exit(0);
return;
case "search": // Search for the occurrances of n in memory
if (cmds.Length == 2)
{
ushort val = parseValue(cmds[1]);
Console.WriteLine("Searching memory...");
for (int i = vm.memory.Length - 1; i != 0; --i)
{
if (vm.memory[i] == val)
{
Console.WriteLine("{0}: {1}\t('{2}')", i, val, (char)val);
}
}
Console.WriteLine("Complete.");
}
else
{
Console.WriteLine("Target Monitor: search requires one argument.");
}
break;
case "hb":
case "haltbreak": // examines / sets haltbreak
Console.WriteLine("haltBreak={0}", haltBreak);
if (cmds.Length == 2)
{
haltBreak = parseBool(cmds[1]);
Console.WriteLine("haltBreak={0}\tCHANGED", haltBreak);
}
break;
case "nb":
case "noopbreak": // examines / sets noopBreak
Console.WriteLine("noopBreak={0}", noopBreak);
if (cmds.Length == 2)
{
noopBreak = parseBool(cmds[1]);
Console.WriteLine("noopBreak={0}\tCHANGED", noopBreak);
}
break;
case "setsp":
vm.SP = parseAddr(cmds[1]);
Console.WriteLine("SP={0}\tCHANGED", vm.SP);
break;
case "setfp":
vm.FP = parseAddr(cmds[1]);
Console.WriteLine("FP={0}\tCHANGED", vm.FP);
break;
case "setmp":
vm.MP = parseAddr(cmds[1]);
Console.WriteLine("MP={0}\tCHANGED", vm.MP);
break;
case "store":
if (cmds.Length == 3)
{
ushort storeAddr = parseAddr(cmds[1]);
ushort storeVal = parseValue(cmds[2]);
vm.memory[storeAddr] = storeVal;
Console.WriteLine("{0}:\t{1}", storeAddr, storeVal);
}
else
{
Console.WriteLine("Target Monitor: store takes 2 arguments (address, value)");
}
break;
case "push":
ushort data = parseAddr(cmds[1]);;
vm.push(data);
Console.WriteLine("Pushed {0} onto the stack.", data);
break;
case "pop":
if (vm.SP > 0)
{
Console.WriteLine("Popped {0} from the stack.", vm.pop());
}
else
{
Console.WriteLine("Stack at top of address space. Cannot pop.");
}
break;
case "j":
case "jump":
if (cmds.Length == 2)
{
vm.PC = parseAddr(cmds[1]);
Console.WriteLine("Jumping to {0}", vm.PC);
this.op = vm.getNextInstruction(); // Decode the instruction and execute it instead
}
else
{
Console.WriteLine("Target Monitor: jump requires an argument. Example: jump 50");
}
break;
case "d":
case "decode":
for (int i = 1; i < cmds.Length; i++)
{
ushort addr = parseAddr(cmds[i]);
CpuInstruction memop = new CpuInstruction();
memop[0] = vm.memory[addr];
memop[1] = vm.memory[addr + 1];
Console.WriteLine("{0}:\t{1}", addr, memop.ToString());
}
if (cmds.Length == 1)
{
Console.WriteLine("{0}\t{1}", (vm.PC - 2), op.ToString());
}
break;
case "i":
case "inspect":
for (int i = 1; i < cmds.Length; i++)
{
ushort addr = parseAddr(cmds[i]);
if (signedAccess)
{
if (addr < vm.memory.Length)
{
Console.WriteLine("{0}:\t0x{1:X4} == {1}s", addr, (short)vm.memory[addr]);
}
else
{
Console.WriteLine("{0}:\tOUT OF BOUNDS");
}
}
else
{
if (addr < vm.memory.Length)
{
Console.WriteLine("{0}:\t0x{1:X4} == {1}u", addr, vm.memory[addr]);
}
else
{
Console.WriteLine("{0}:\tOUT OF BOUNDS");
}
}
}
break;
case "p":
case "peek":
ushort pitems = 1;
bool peekSigned = signedAccess;
if (cmds.Length == 2)
{
pitems = parseAddr(cmds[1]);
}
// Check we're not about to read out of the memory bounds
if (vm.SP - pitems < 0)
{
Console.WriteLine("Target Monitor: {0} word{1} back from SP ({2}) is an illegal address.", pitems, (pitems != 1 ? "s" : ""), vm.SP);
break;
}
for (int offset = 1; offset <= pitems; offset++)
{
ushort w = vm.memory[vm.SP - offset]; // vm.memGetWord(vm.SP - offset);
if (peekSigned)
{
Console.WriteLine("{0}:\t0x{1:X4} == {1}s", vm.SP - offset, (short)w);
}
else
{
Console.WriteLine("{0}:\t0x{1:X4} == {1}u", vm.SP - offset, w);
}
}
break;
case "g":
case "reg":
case "registers":
case "register":
case "calc": // make it easier for the user to think about using reg to calculate values
if (cmds.Length == 1)
{
Hashtable core = vm.coreDump();
foreach (string key in core.Keys)
{
Console.WriteLine("{0}\t= {1}", key, core[key]);
}
}
else
{
for (int i = 1; i < cmds.Length; i++)
{
ushort val = parseAddr(cmds[i]);
Console.WriteLine("{0} = {1}", cmds[i].ToUpper(), val);
}
}
break;
case "assemble":
case "asm":
if (cmds.Length >= 2)
{
// Assemble each file passed in as an argument
for (int i = 1; i < cmds.Length; i++)
{
if (File.Exists(cmds[i]))
{
Assembler a = new Assembler(vm.memory, cmds[i]);
vm.memory = a.getAssembled(); // technically unnecessary
// Re-decode this instruction (in case it's changed)
vm.PC -= 2;
this.op = vm.getNextInstruction();
}
else
{
Console.WriteLine("Arg #{0} Non-existant file {1}", i, cmds[i]);
}
}
}
else
{
Console.WriteLine("Monitor: assemble requires a parameter. Please quote paths with spaces in them.");
}
break;
case "t":
case "trace":
case "savetrace":
if (cmds.Length == 2)
{
Console.WriteLine("Monitor: Tracing Enabled");
startTrace(cmds[1]);
}
else
{
Console.WriteLine("Monitor: trace requires one parameter");
}
break;
case "logio":
case "lio":
case "io":
case "l":
if (cmds.Length == 2)
{
Console.WriteLine("Monitor: IO Logging Enabled");
startIOLog(cmds[1].Replace('_', ' '));
}
else
{
Console.WriteLine("Monitor: logio requires one parameter. Please quote paths with spaces in them.");
}
break;
case "signed":
signedAccess = true;
Console.WriteLine("Monitor: memory display set to signed");
break;
case "unsigned":
signedAccess = false;
Console.WriteLine("Monitor: memory display set to unsigned");
break;
case "?":
case "help":
#if DOTNET2
Console.BackgroundColor = ConsoleColor.Blue;
Console.ForegroundColor = ConsoleColor.White;
#endif
Console.WriteLine("TARGET MONITOR - QUICK HELP");
#if DOTNET2
Console.ResetColor();
#endif
Console.WriteLine("Copyright (c) 2006, Peter Wright <*****@*****.**>");
Console.WriteLine("Commands that take n can understand 'sp', '0,[fp,1]', etc.");
Console.WriteLine("d {n} - Displays a decode of the instruction[s] at n.");
Console.WriteLine(" Current instruction displayed if none are");
Console.WriteLine(" specified (decode)");
Console.WriteLine("p [-][n] - Displays the top n items on the stack. (peek)");
Console.WriteLine("i [-]{n} - Displays values stored in memory location[s] n.");
Console.WriteLine("j addr - Branches immediately to ADDR. (jump)");
Console.WriteLine("q - Terminates the VM immediately");
Console.WriteLine("c - Resumes execution; monitor state unchanged");
Console.WriteLine(" (continue, <ENTER>)");
Console.WriteLine("r - Resumes execution; monitor disabled");
Console.WriteLine("n - Resumes execution; monitor enabled");
Console.WriteLine("k n - Hides monitor for another n operations. (skip)");
Console.WriteLine("b n - Hides monitor until operation at n. (break)");
Console.WriteLine("g - Displays all registers (registers)");
Console.WriteLine("g {n} - Displays specific register values");
Console.WriteLine("calc {n} - Calculates the address n");
Console.WriteLine("asm f - Assembles file f");
Console.WriteLine("t f - Starts saving trace data to file f");
Console.WriteLine("l f - Logs all IO to file f");
Console.WriteLine("signed - Changes memory display to signed mode");
break;
default:
Console.WriteLine("Monitor: Unknown command");
break;
}
}
#endregion
}
