Path: blob/master/BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.cs
2 views
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using BizHawk.Common;
using BizHawk.Emulation.Cores.Computers.Commodore64.Media;
namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
{
public sealed partial class Via
{
[SaveState.DoNotSave] private const int PCR_INT_CONTROL_NEGATIVE_EDGE = 0x00;
[SaveState.DoNotSave] private const int PCR_INT_CONTROL_POSITIVE_EDGE = 0x01;
[SaveState.DoNotSave] private const int PCR_CONTROL_INPUT_NEGATIVE_ACTIVE_EDGE = 0x00;
[SaveState.DoNotSave] private const int PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE = 0x02;
[SaveState.DoNotSave] private const int PCR_CONTROL_INPUT_POSITIVE_ACTIVE_EDGE = 0x04;
[SaveState.DoNotSave] private const int PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE = 0x06;
[SaveState.DoNotSave] private const int PCR_CONTROL_HANDSHAKE_OUTPUT = 0x08;
[SaveState.DoNotSave] private const int PCR_CONTROL_PULSE_OUTPUT = 0x0A;
[SaveState.DoNotSave] private const int PCR_CONTROL_LOW_OUTPUT = 0x0C;
[SaveState.DoNotSave] private const int PCR_CONTROL_HIGH_OUTPUT = 0x0E;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_DISABLED = 0x00;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_IN_T2_ONCE = 0x04;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_IN_PHI2 = 0x08;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_IN_CLOCK = 0x0C;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_OUT_T2 = 0x10;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_OUT_T2_ONCE = 0x14;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_OUT_PHI2 = 0x18;
[SaveState.DoNotSave] private const int ACR_SR_CONTROL_SHIFT_OUT_CLOCK = 0x1C;
[SaveState.DoNotSave] private const int ACR_T2_CONTROL_TIMED = 0x00;
[SaveState.DoNotSave] private const int ACR_T2_CONTROL_COUNT_ON_PB6 = 0x20;
[SaveState.DoNotSave] private const int ACR_T1_CONTROL_INTERRUPT_ON_LOAD = 0x00;
[SaveState.DoNotSave] private const int ACR_T1_CONTROL_CONTINUOUS_INTERRUPTS = 0x40;
[SaveState.DoNotSave] private const int ACR_T1_CONTROL_INTERRUPT_ON_LOAD_AND_ONESHOT_PB7 = 0x80;
[SaveState.DoNotSave] private const int ACR_T1_CONTROL_CONTINUOUS_INTERRUPTS_AND_OUTPUT_ON_PB7 = 0xC0;
[SaveState.SaveWithName("PortOutputA")]
private int _pra;
[SaveState.SaveWithName("PortDirectionA")]
private int _ddra;
[SaveState.SaveWithName("PortOutputB")]
private int _prb;
[SaveState.SaveWithName("PortDirectionB")]
private int _ddrb;
[SaveState.SaveWithName("Timer1Counter")]
private int _t1C;
[SaveState.SaveWithName("Timer1Latch")]
private int _t1L;
[SaveState.SaveWithName("Timer2Counter")]
private int _t2C;
[SaveState.SaveWithName("Timer2Latch")]
private int _t2L;
[SaveState.SaveWithName("ShiftRegister")]
private int _sr;
[SaveState.SaveWithName("AuxiliaryControlRegister")]
private int _acr;
[SaveState.SaveWithName("PeripheralControlRegister")]
private int _pcr;
[SaveState.SaveWithName("InterruptFlagRegister")]
private int _ifr;
[SaveState.SaveWithName("InterruptEnableRegister")]
private int _ier;
[SaveState.SaveWithName("Port")]
private readonly Port _port;
[SaveState.SaveWithName("PortLatchA")]
private int _paLatch;
[SaveState.SaveWithName("PortLatchB")]
private int _pbLatch;
[SaveState.SaveWithName("CA1InterruptControl")]
private int _pcrCa1IntControl;
[SaveState.SaveWithName("CA2Control")]
private int _pcrCa2Control;
[SaveState.SaveWithName("CB1InterruptControl")]
private int _pcrCb1IntControl;
[SaveState.SaveWithName("CB2Control")]
private int _pcrCb2Control;
[SaveState.SaveWithName("PortLatchEnableA")]
private bool _acrPaLatchEnable;
[SaveState.SaveWithName("PortLatchEnableB")]
private bool _acrPbLatchEnable;
[SaveState.SaveWithName("ShiftRegisterControl")]
private int _acrSrControl;
[SaveState.SaveWithName("Timer1Control")]
private int _acrT1Control;
[SaveState.SaveWithName("Timer2Control")]
private int _acrT2Control;
[SaveState.SaveWithName("PreviousCA1")]
private bool _ca1L;
[SaveState.SaveWithName("PreviousCA2")]
private bool _ca2L;
[SaveState.SaveWithName("PreviousCB1")]
private bool _cb1L;
[SaveState.SaveWithName("PreviousCB2")]
private bool _cb2L;
[SaveState.SaveWithName("PreviousPB6")]
private bool _pb6L;
[SaveState.SaveWithName("ResetCa2NextClock")]
private bool _resetCa2NextClock;
[SaveState.SaveWithName("ResetCb2NextClock")]
private bool _resetCb2NextClock;
[SaveState.SaveWithName("HandshakeCa2NextClock")]
private bool _handshakeCa2NextClock;
[SaveState.SaveWithName("HandshakeCb2NextClock")]
private bool _handshakeCb2NextClock;
[SaveState.SaveWithName("CA1")]
public bool Ca1;
[SaveState.SaveWithName("CA2")]
public bool Ca2;
[SaveState.SaveWithName("CB1")]
public bool Cb1;
[SaveState.SaveWithName("CB2")]
public bool Cb2;
[SaveState.SaveWithName("PB6")]
private bool _pb6;
[SaveState.SaveWithName("InterruptNextClock")]
private int _interruptNextClock;
[SaveState.SaveWithName("T1Loaded")]
private bool _t1CLoaded;
[SaveState.SaveWithName("T2Loaded")]
private bool _t2CLoaded;
[SaveState.SaveWithName("T1Delayed")]
private int _t1Delayed;
[SaveState.SaveWithName("T2Delayed")]
private int _t2Delayed;
public Via()
{
_port = new DisconnectedPort();
}
public Via(Func<int> readPrA, Func<int> readPrB)
{
_port = new DriverPort(readPrA, readPrB);
}
public Via(Func<bool> readClock, Func<bool> readData, Func<bool> readAtn, int driveNumber)
{
_port = new IecPort(readClock, readData, readAtn, driveNumber);
_ca1L = true;
}
[SaveState.DoNotSave]
public bool Irq
{
get { return (_ifr & 0x80) == 0; }
}
public void HardReset()
{
_pra = 0;
_prb = 0;
_ddra = 0;
_ddrb = 0;
_t1C = 0;
_t1L = 0;
_t2C = 0;
_t2L = 0;
_sr = 0;
_acr = 0;
_pcr = 0;
_ifr = 0;
_ier = 0;
_paLatch = 0;
_pbLatch = 0;
_pcrCa1IntControl = 0;
_pcrCa2Control = 0;
_pcrCb1IntControl = 0;
_pcrCb2Control = 0;
_acrPaLatchEnable = false;
_acrPbLatchEnable = false;
_acrSrControl = 0;
_acrT1Control = 0;
_acrT2Control = 0;
_ca1L = false;
_cb1L = false;
Ca1 = false;
Ca2 = false;
Cb1 = false;
Cb2 = false;
_pb6L = false;
_pb6 = false;
_resetCa2NextClock = false;
_resetCb2NextClock = false;
_handshakeCa2NextClock = false;
_handshakeCb2NextClock = false;
_interruptNextClock = 0;
_t1CLoaded = false;
_t2CLoaded = false;
}
public void ExecutePhase()
{
// Process delayed interrupts
_ifr |= _interruptNextClock;
_interruptNextClock = 0;
// Process 'pulse' and 'handshake' outputs on CA2 and CB2
if (_resetCa2NextClock)
{
Ca2 = true;
_resetCa2NextClock = false;
}
else if (_handshakeCa2NextClock)
{
Ca2 = false;
_resetCa2NextClock = _pcrCa2Control == PCR_CONTROL_PULSE_OUTPUT;
_handshakeCa2NextClock = false;
}
if (_resetCb2NextClock)
{
Cb2 = true;
_resetCb2NextClock = false;
}
else if (_handshakeCb2NextClock)
{
Cb2 = false;
_resetCb2NextClock = _pcrCb2Control == PCR_CONTROL_PULSE_OUTPUT;
_handshakeCb2NextClock = false;
}
// Count timers
if (_t1Delayed > 0)
{
_t1Delayed--;
}
else
{
_t1C--;
if (_t1C < 0)
{
if (_t1CLoaded)
{
_interruptNextClock |= 0x40;
_t1CLoaded = false;
}
switch (_acrT1Control)
{
case ACR_T1_CONTROL_CONTINUOUS_INTERRUPTS:
_t1C = _t1L;
_t1CLoaded = true;
break;
case ACR_T1_CONTROL_CONTINUOUS_INTERRUPTS_AND_OUTPUT_ON_PB7:
_t1C = _t1L;
_prb ^= 0x80;
_t1CLoaded = true;
break;
}
_t1C &= 0xFFFF;
}
}
if (_t2Delayed > 0)
{
_t2Delayed--;
}
else
{
switch (_acrT2Control)
{
case ACR_T2_CONTROL_TIMED:
_t2C--;
if (_t2C < 0)
{
if (_t2CLoaded)
{
_interruptNextClock |= 0x20;
_t2CLoaded = false;
}
_t2C = _t2L;
}
break;
case ACR_T2_CONTROL_COUNT_ON_PB6:
_pb6L = _pb6;
_pb6 = (_port.ReadExternalPrb() & 0x40) != 0;
if (!_pb6 && _pb6L)
{
_t2C--;
if (_t2C < 0)
{
_ifr |= 0x20;
_t2C = 0xFFFF;
}
}
break;
}
}
// Process CA2
switch (_pcrCa2Control)
{
case PCR_CONTROL_INPUT_NEGATIVE_ACTIVE_EDGE:
case PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE:
if (_ca2L && !Ca2)
_ifr |= 0x01;
break;
case PCR_CONTROL_INPUT_POSITIVE_ACTIVE_EDGE:
case PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE:
if (!_ca2L && Ca2)
_ifr |= 0x01;
break;
case PCR_CONTROL_HANDSHAKE_OUTPUT:
if (_ca1L && !Ca1)
{
Ca2 = true;
_ifr |= 0x01;
}
break;
case PCR_CONTROL_PULSE_OUTPUT:
break;
case PCR_CONTROL_LOW_OUTPUT:
Ca2 = false;
break;
case PCR_CONTROL_HIGH_OUTPUT:
Ca2 = true;
break;
}
// Process CB2
switch (_pcrCb2Control)
{
case PCR_CONTROL_INPUT_NEGATIVE_ACTIVE_EDGE:
case PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE:
if (_cb2L && !Cb2)
_ifr |= 0x08;
break;
case PCR_CONTROL_INPUT_POSITIVE_ACTIVE_EDGE:
case PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE:
if (!_cb2L && Cb2)
_ifr |= 0x08;
break;
case PCR_CONTROL_HANDSHAKE_OUTPUT:
if (_cb1L && !Cb1)
{
Cb2 = true;
_ifr |= 0x08;
}
break;
case PCR_CONTROL_PULSE_OUTPUT:
break;
case PCR_CONTROL_LOW_OUTPUT:
Cb2 = false;
break;
case PCR_CONTROL_HIGH_OUTPUT:
Cb2 = true;
break;
}
// interrupt generation
if ((_pcrCb1IntControl == PCR_INT_CONTROL_POSITIVE_EDGE && Cb1 && !_cb1L) ||
(_pcrCb1IntControl == PCR_INT_CONTROL_NEGATIVE_EDGE && !Cb1 && _cb1L))
{
_ifr |= 0x10;
if (_acrPbLatchEnable)
{
_pbLatch = _port.ReadExternalPrb();
}
}
if ((_pcrCa1IntControl == PCR_INT_CONTROL_POSITIVE_EDGE && Ca1 && !_ca1L) ||
(_pcrCa1IntControl == PCR_INT_CONTROL_NEGATIVE_EDGE && !Ca1 && _ca1L))
{
_ifr |= 0x02;
if (_acrPaLatchEnable)
{
_paLatch = _port.ReadExternalPra();
}
}
switch (_acrSrControl)
{
case ACR_SR_CONTROL_DISABLED:
_ifr &= 0xFB;
break;
default:
break;
}
if ((_ifr & _ier & 0x7F) != 0)
{
_ifr |= 0x80;
}
else
{
_ifr &= 0x7F;
}
_ca1L = Ca1;
_ca2L = Ca2;
_cb1L = Cb1;
_cb2L = Cb2;
}
public void SyncState(Serializer ser)
{
SaveState.SyncObject(ser, this);
}
}
}