private void MoveToNextHalfWord()
{
if (_immediateHalf == ImmediateHalf.Second)
{
_pc++;
_immediateWord = _mem.Fetch(_pc);
_immediateHalf = ImmediateHalf.First;
// Update the instruction cache with the type of instruction (to aid in debugging).
PDS1DisplayInstruction instruction = GetCachedInstruction(_pc, DisplayProcessorMode.Increment);
}
else
{
_immediateHalf = ImmediateHalf.Second;
}
}
public override void InitializeCache()
{
_instructionCache = new PDS1DisplayInstruction[Memory.Size];
}
private void ExecuteProcessor()
{
PDS1DisplayInstruction instruction = GetCachedInstruction(_pc, DisplayProcessorMode.Processor);
instruction.UsageMode = DisplayProcessorMode.Processor;
switch (instruction.Opcode)
{
case DisplayOpcode.DEIM:
_mode = DisplayProcessorMode.Increment;
_immediateWord = instruction.Data;
_immediateHalf = ImmediateHalf.Second;
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "Enter increment mode");
}
break;
case DisplayOpcode.DJMP:
if (!_dadr)
{
// DADR off, use only 12 bits
_pc = (ushort)((instruction.Data & 0xfff) | _block);
}
else
{
_pc = (ushort)(instruction.Data | _block);
}
break;
case DisplayOpcode.DJMS:
Push();
if (!_dadr)
{
// DADR off, use only 12 bits
_pc = (ushort)((instruction.Data & 0xfff) | _block);
}
else
{
_pc = (ushort)(instruction.Data | _block);
}
break;
case DisplayOpcode.DOPR:
// Each of bits 4-11 can be combined in any fashion
// to do a number of operations simultaneously; we walk the bits
// and perform the operations as set.
if ((instruction.Data & 0x800) == 0)
{
// DHLT -- halt the display processor. other micro-ops in this
// instruction are still run.
HaltProcessor();
}
if ((instruction.Data & 0x400) != 0)
{
// HV Sync; this is currently a no-op, not much to do in emulation.
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "HV Sync");
}
_system.Display.MoveAbsolute(X, Y, DrawingMode.Off);
}
if ((instruction.Data & 0x200) != 0)
{
// DIXM -- increment X DAC MSB
X += 0x20;
_system.Display.MoveAbsolute(X, Y, DrawingMode.Off);
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "DIXM, X is now {0}", X);
}
}
if ((instruction.Data & 0x100) != 0)
{
// DIYM -- increment Y DAC MSB
Y += 0x20;
_system.Display.MoveAbsolute(X, Y, DrawingMode.Off);
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "DIYM, Y is now {0}", Y);
}
}
if ((instruction.Data & 0x80) != 0)
{
// DDXM - decrement X DAC MSB
X -= 0x20;
_system.Display.MoveAbsolute(X, Y, DrawingMode.Off);
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "DDXM, X is now {0}", X);
}
}
if ((instruction.Data & 0x40) != 0)
{
// DDYM - decrement y DAC MSB
Y -= 0x20;
_system.Display.MoveAbsolute(X, Y, DrawingMode.Off);
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "DDYM, Y is now {0}", Y);
}
}
if ((instruction.Data & 0x20) != 0)
{
// DRJM - return from display subroutine
ReturnFromDisplaySubroutine();
_pc--; // hack (we add +1 at the end...)
}
if ((instruction.Data & 0x10) != 0)
{
// DDSP -- intensify point on screen for 1.8us (one instruction)
// at the current position.
_system.Display.DrawPoint(X, Y);
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "DDSP at {0},{1}", X, Y);
}
}
// F/C ops:
int f = (instruction.Data & 0xc) >> 2;
int c = instruction.Data & 0x3;
switch (f)
{
case 0x0:
// if bit 15 is set, the MIT mods flip the DADR bit.
if (Configuration.MITMode && (c == 1))
{
_dadr = !_dadr;
}
break;
case 0x1:
// Set scale based on C
switch (c)
{
case 0:
_scale = 1.0f;
break;
default:
_scale = c;
break;
}
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "Scale set to {0}", _scale);
}
break;
case 0x2:
if (!Configuration.MITMode)
{
_block = (ushort)(c << 12);
}
break;
case 0x3:
// TODO: light pen sensitize
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "Light pen, stub!");
}
break;
}
_pc++;
break;
case DisplayOpcode.DLXA:
X = instruction.Data << 1;
DrawingMode mode;
if (_sgrModeOn && _sgrBeamOn)
{
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "SGR-1 X set to {0}", X);
}
mode = DrawingMode.SGR1;
}
else
{
mode = DrawingMode.Off;
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "X set to {0}", X);
}
}
_system.Display.MoveAbsolute(X, Y, mode);
if (_sgrDJRMOn)
{
ReturnFromDisplaySubroutine();
}
else
{
_pc++;
}
break;
case DisplayOpcode.DLYA:
Y = instruction.Data << 1;
if (_sgrModeOn && _sgrBeamOn)
{
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "SGR-1 Y set to {0}", Y);
}
mode = DrawingMode.SGR1;
}
else
{
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "Y set to {0}", Y);
}
mode = DrawingMode.Off;
}
_system.Display.MoveAbsolute(X, Y, mode);
if (_sgrDJRMOn)
{
ReturnFromDisplaySubroutine();
}
else
{
_pc++;
}
break;
case DisplayOpcode.DLVH:
DrawLongVector(instruction.Data);
break;
case DisplayOpcode.SGR1:
_sgrModeOn = (instruction.Data & 0x1) != 0;
_sgrDJRMOn = (instruction.Data & 0x2) != 0;
_sgrBeamOn = (instruction.Data & 0x4) != 0;
if (Trace.TraceOn)
{
Trace.Log(LogType.DisplayProcessor, "SGR-1 instruction: Enter {0} BeamOn {1} DRJM {2}", _sgrModeOn, _sgrBeamOn, _sgrDJRMOn);
}
_pc++;
break;
default:
throw new NotImplementedException(String.Format("Unimplemented Display Processor Opcode {0}, operands {1}", Helpers.ToOctal((ushort)instruction.Opcode), Helpers.ToOctal(instruction.Data)));
}
// If the next instruction has a breakpoint set we'll halt at this point, before executing it.
if (BreakpointManager.TestBreakpoint(BreakpointType.Display, _pc))
{
_state = ProcessorState.BreakpointHalt;
}
}