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C64: Implement more VIA features.

This commit is contained in:
SaxxonPike 2019-07-04 00:23:11 -05:00
parent 7fbccb7a46
commit 32d59e8514
3 changed files with 45 additions and 48 deletions
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4
BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Port.cs
View File

@ -56,7 +56,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
public int ReadPra(int pra, int ddra)
{
return _readPrA();
return (pra | ~ddra) & ReadExternalPra();
}
public int ReadPrb(int prb, int ddrb)
@ -98,7 +98,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
public int ReadPra(int pra, int ddra)
{
return (pra | ~ddra) & 0xFF;
return (pra | ~ddra) & ReadExternalPra();
}
public int ReadPrb(int prb, int ddrb)

32
BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.Registers.cs
View File

@ -18,18 +18,16 @@
switch (addr)
{
case 0x0:
_ifr &= 0xE7;
if (_pcrCb2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE && _pcrCb2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE)
_ifr &= 0xE7;
if (_acrPbLatchEnable)
{
return _pbLatch;
}
break;
case 0x1:
_ifr &= 0xFC;
if (_pcrCa2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE && _pcrCa2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE)
_ifr &= 0xFC;
if (_acrPaLatchEnable)
{
return _paLatch;
}
break;
case 0x4:
_ifr &= 0xBF;
@ -39,6 +37,7 @@
break;
case 0xA:
_ifr &= 0xFB;
_srCount = 8;
break;
case 0xF:
if (_acrPaLatchEnable)
@ -58,6 +57,7 @@
case 0x0:
return _port.ReadPrb(_prb, _ddrb);
case 0x1:
case 0xF:
return _port.ReadExternalPra();
case 0x2:
return _ddrb;
@ -85,8 +85,6 @@
return _ifr;
case 0xE:
return _ier | 0x80;
case 0xF:
return _port.ReadExternalPra();
}
return 0xFF;
@ -98,20 +96,17 @@
switch (addr)
{
case 0x0:
_ifr &= 0xE7;
if (_pcrCb2Control == PCR_CONTROL_HANDSHAKE_OUTPUT || _pcrCb2Control == PCR_CONTROL_PULSE_OUTPUT)
{
if (_pcrCb2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE && _pcrCb2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE)
_ifr &= 0xE7;
if (_pcrCb2Control == PCR_CONTROL_PULSE_OUTPUT)
_handshakeCb2NextClock = true;
}
WriteRegister(addr, val);
break;
case 0x1:
_ifr &= 0xFC;
if (_pcrCa2Control == PCR_CONTROL_HANDSHAKE_OUTPUT || _pcrCa2Control == PCR_CONTROL_PULSE_OUTPUT)
{
if (_pcrCa2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_NEGATIVE_EDGE && _pcrCa2Control != PCR_CONTROL_INDEPENDENT_INTERRUPT_INPUT_POSITIVE_EDGE)
_ifr &= 0xFC;
if (_pcrCa2Control == PCR_CONTROL_PULSE_OUTPUT)
_handshakeCa2NextClock = true;
}
WriteRegister(addr, val);
break;
case 0x4:
@ -146,6 +141,7 @@
break;
case 0xA:
_ifr &= 0xFB;
_srCount = 8;
WriteRegister(addr, val);
break;
case 0xD:
@ -238,7 +234,7 @@
public int EffectivePrB => _prb | ~_ddrb;
public int ActualPrA => _acrPaLatchEnable ? _paLatch : _port.ReadExternalPra();
public int ActualPrA => _acrPaLatchEnable ? _paLatch : _port.ReadPra(_pra, _ddra);
public int ActualPrB => _acrPbLatchEnable ? _pbLatch : _port.ReadPrb(_prb, _ddrb);
}

57
BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Via.cs
View File

@ -58,6 +58,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
private int _acrSrControl;
private int _acrT1Control;
private int _acrT2Control;
private int _srCount;
private bool _ca1L;
private bool _ca2L;
@ -135,6 +136,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
Ca2 = true;
Cb1 = true;
Cb2 = true;
_srCount = 0;
_pb6L = true;
_pb6 = true;
@ -151,6 +153,9 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
public void ExecutePhase()
{
var _shiftIn = false;
var _shiftOut = false;
// Process delayed interrupts
_ifr |= _interruptNextClock;
_interruptNextClock = 0;
@ -259,9 +264,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
{
_t2C--;
if (_t2C == 0)
{
_ifr |= 0x20;
}
_t2C &= 0xFFFF;
}
break;
@ -330,24 +333,28 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
// interrupt generation
/*
As long as the CA1 interrupt flag is set, the data on the peripheral pins can change
without affecting the data in the latches. This input latching can be used with any of the CA2
input or output modes.
It is important to note that on the PA port, the processor always reads the data on the
peripheral pins (as reflected in the latches). For output pins, the processor still reads the
latches. This may or may not reflect the data currently in the ORA. Proper system operation
requires careful planning on the part of the system designer if input latching is combined
with output pins on the peripheral ports.
*/
if (_acrSrControl == ACR_SR_CONTROL_DISABLED)
{
_ifr &= 0xFB;
_srCount = 0;
}
/*
As long as the CA1 interrupt flag is set, the data on the peripheral pins can change
without affecting the data in the latches. This input latching can be used with any of the CA2
input or output modes.
It is important to note that on the PA port, the processor always reads the data on the
peripheral pins (as reflected in the latches). For output pins, the processor still reads the
latches. This may or may not reflect the data currently in the ORA. Proper system operation
requires careful planning on the part of the system designer if input latching is combined
with output pins on the peripheral ports.
*/
if ((_pcrCa1IntControl == PCR_INT_CONTROL_POSITIVE_EDGE && Ca1 && !_ca1L) ||
(_pcrCa1IntControl == PCR_INT_CONTROL_NEGATIVE_EDGE && !Ca1 && _ca1L))
{
if (_acrPaLatchEnable && (_ifr & 0x02) == 0)
{
_paLatch = _port.ReadExternalPra();
}
_paLatch = _port.ReadExternalPra();
_ifr |= 0x02;
}
@ -362,29 +369,22 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
(_pcrCb1IntControl == PCR_INT_CONTROL_NEGATIVE_EDGE && !Cb1 && _cb1L))
{
if (_acrPbLatchEnable && (_ifr & 0x10) == 0)
{
_pbLatch = _port.ReadPrb(_prb, _ddrb);
}
_pbLatch = _port.ReadPrb(_prb, _ddrb);
if (_acrSrControl == ACR_SR_CONTROL_DISABLED)
_shiftIn = true;
_ifr |= 0x10;
}
switch (_acrSrControl)
if (_shiftIn)
{
case ACR_SR_CONTROL_DISABLED:
_ifr &= 0xFB;
break;
default:
break;
_sr <<= 1;
_sr |= Cb2 ? 1 : 0;
}
if ((_ifr & _ier & 0x7F) != 0)
{
_ifr |= 0x80;
}
else
{
_ifr &= 0x7F;
}
_ca1L = Ca1;
_ca2L = Ca2;
@ -444,6 +444,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
ser.Sync("T2Delayed", ref _t2Delayed);
ser.Sync("ResetPb7NextClock", ref _resetPb7NextClock);
ser.Sync("SetPb7NextClock", ref _setPb7NextClock);
ser.Sync("ShiftRegisterCount", ref _srCount);
}
}
}