private static string DisassembleEmulatorSpecialFunction1(MicroInstruction instruction)
{
EmulatorF1 ef1 = (EmulatorF1)instruction.F1;
switch (ef1)
{
case EmulatorF1.SWMODE:
return("SWMODE ");
case EmulatorF1.WRTRAM:
return("WRTRAM ");
case EmulatorF1.RDRAM:
return("RDRAM ");
case EmulatorF1.LoadRMR:
return("RMR← ");
case EmulatorF1.LoadESRB:
return("ESRB← ");
case EmulatorF1.RSNF:
return("RSNF ");
case EmulatorF1.STARTF:
return("STARTF ");
default:
return(String.Format("F1 {0}", Conversion.ToOctal((int)ef1)));
}
}
protected override void ExecuteSpecialFunction1Early(MicroInstruction instruction)
{
EmulatorF1 ef1 = (EmulatorF1)instruction.F1;
switch (ef1)
{
case EmulatorF1.RSNF:
//
// Early:
// "...decoded by the Ethernet interface, which gates the host address wired on the
// backplane onto BUS[8-15]. BUS[0-7] is not driven and will therefore be -1. If
// no Ethernet interface is present, BUS will be -1.
//
_busData &= (ushort)((0xff00 | _cpu._system.EthernetController.Address));
break;
}
}
protected override void ExecuteSpecialFunction1(MicroInstruction instruction)
{
EmulatorF1 ef1 = (EmulatorF1)instruction.F1;
switch (ef1)
{
case EmulatorF1.LoadRMR:
//
// "The emulator F1 RMR<- causes the reset mode register to be loaded from the processor bus. The 16 bits of the
// processor bus correspond to the 16 Alto tasks in the following way: the low order bit of the processor
// bus specifies the initial mode of task 0, the lowest priority task (emulator), and the high-order bit of the
// bus specifies the initial mode of task 15, the highest priority task(recall that task i starts at location i; the
// reset mode register determines only which microinstruction bank will be used at the outset). A task will
// commence in ROM0 if its associated bit in the reset mode register contains the value 1; otherwise it will
// start in RAM0.Upon initial power - up of the Alto, and after each reset operation, the reset mode register
// is automatically set to all ones, corresponding to starting all tasks in ROM0."
//
_cpu._rmr = _busData;
break;
case EmulatorF1.RSNF:
// Handled in the Early handler.
break;
case EmulatorF1.STARTF:
// Dispatch function to Ethernet I/O based on contents of AC0.
if ((_busData & 0x8000) != 0)
{
//
// BOOT (soft-reset) operation.
// Reset the CPU using the current RMR (start tasks in RAM or ROM as specified.)
_cpu.SoftReset();
// Since this is a soft reset, we don't want MPC to be taken from the NEXT
// field at the end of the cycle, setting this flag causes the main Task
// implementation to skip updating _mpc at the end of this instruction.
_softReset = true;
}
else if (_busData != 0)
{
//
// Dispatch to the appropriate device.
//
switch (_busData)
{
case 1:
case 2:
case 3:
// Ethernet
_cpu._system.EthernetController.STARTF(_busData);
break;
case 4:
// Orbit
_cpu._system.OrbitController.STARTF(_busData);
break;
default:
Log.Write(Logging.LogType.Warning, Logging.LogComponent.EmulatorTask, "STARTF for non-Ethernet device (code {0})",
Conversion.ToOctal(_busData));
break;
}
}
break;
case EmulatorF1.SWMODE:
_swMode = true;
break;
case EmulatorF1.RDRAM:
_rdRam = true;
break;
case EmulatorF1.WRTRAM:
_wrtRam = true;
break;
case EmulatorF1.LoadESRB:
_rb = (ushort)((_busData & 0xe) >> 1);
if (_rb != 0 && _systemType != SystemType.ThreeKRam)
{
// Force bank 0 for machines with only 1K RAM.
_rb = 0;
}
break;
default:
throw new InvalidOperationException(String.Format("Unhandled emulator F1 {0}.", ef1));
}
}
protected override void ExecuteSpecialFunction1(MicroInstruction instruction)
{
EmulatorF1 ef1 = (EmulatorF1)instruction.F1;
switch (ef1)
{
case EmulatorF1.LoadRMR:
//
// "The emulator F1 RMR<- causes the reset mode register to be loaded from the processor bus. The 16 bits of the
// processor bus correspond to the 16 Alto tasks in the following way: the low order bit of the processor
// bus specifies the initial mode of task 0, the lowest priority task (emulator), and the high-order bit of the
// bus specifies the initial mode of task 15, the highest priority task(recall that task i starts at location i; the
// reset mode register determines only which microinstruction bank will be used at the outset). A task will
// commence in ROM0 if its associated bit in the reset mode register contains the value 1; otherwise it will
// start in RAM0. Upon initial power-up of the Alto, and after each reset operation, the reset mode register
// is automatically set to all ones, corresponding to starting all tasks in ROM0."
//
_cpu._rmr = _busData;
break;
case EmulatorF1.RSNF:
// Handled in the Early handler.
break;
case EmulatorF1.STARTF:
// Dispatch function to Ethernet I/O based on contents of AC0.
if ((_busData & 0x8000) != 0)
{
// Since this is a soft reset, we don't want MPC to be taken from the NEXT
// field at the end of the cycle, setting this flag causes the main Task
// implementation to skip updating _mpc at the end of this instruction.
_softReset = true;
}
else if (_busData != 0)
{
//
// Dispatch to the appropriate device.
//
switch (_busData)
{
case 0x01:
case 0x02:
case 0x03:
// Ethernet
_cpu._system.EthernetController.STARTF(_busData);
break;
case 0x04:
// Orbit
_cpu._system.OrbitController.STARTF(_busData);
break;
case 0x10:
case 0x20:
// Trident start
_cpu._system.TridentController.STARTF(_busData);
break;
//
// The following are not actual Alto STARTF functions,
// these are used to allow writing Alto programs that can
// alter behavior of the emulator. At the moment, these
// are all related to scripting, and are only enabled
// when a script is running.
//
case 0x2000:
//
// Unpause script.
//
if (ScriptManager.IsPlaying)
{
ScriptManager.CompleteWait();
}
break;
case 0x4000:
//
// Emulator exit, commit disks.
//
if (ScriptManager.IsPlaying)
{
throw new ShutdownException(true);
}
break;
default:
Log.Write(Logging.LogType.Warning, Logging.LogComponent.EmulatorTask, "STARTF for unknown device (code {0})",
Conversion.ToOctal(_busData));
break;
}
}
break;
case EmulatorF1.SWMODE:
_swMode = true;
break;
case EmulatorF1.RDRAM:
// TODO: move RDRAM, WRTRAM and S-register BS stuff into the main Task implementation,
// guarded by a check of _ramTask.
_rdRam = true;
break;
case EmulatorF1.WRTRAM:
_wrtRam = true;
break;
case EmulatorF1.LoadESRB:
_rb = (ushort)((_busData & 0xe) >> 1);
if (_rb != 0 && _systemType != SystemType.ThreeKRam)
{
// Force bank 0 for machines with only 1K RAM.
_rb = 0;
}
break;
default:
throw new InvalidOperationException(String.Format("Unhandled emulator F1 {0}.", ef1));
}
}
