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