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Fixed per scanline interrupts. No artifacts in MMCOI

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This commit is contained in:
Marc Parsons
2026-05-15 23:38:40 +01:00
parent 4e745b4fbc
commit f8cb87c4bb
8 changed files with 263 additions and 104 deletions
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70
Core/Audio/SmsApu.cs
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@@ -1,4 +1,5 @@
using Core.Interfaces;
using System.IO;
namespace Core.Audio
{
@@ -196,50 +197,29 @@ namespace Core.Audio
}
}
}
public void SaveState(BinaryWriter bw)
{
for (int i = 0; i < 8; i++) bw.Write(Registers[i]);
bw.Write(_latchedRegister);
bw.Write(_sampleCycleTracker);
bw.Write(_psgCycleTracker);
for (int i = 0; i < 4; i++) { bw.Write(_counters[i]); bw.Write(_polarities[i]); }
bw.Write(_lfsr);
bw.Write(_previousSample);
bw.Write(_previousFiltered);
}
public void LoadState(BinaryReader br)
{
for (int i = 0; i < 8; i++) Registers[i] = br.ReadUInt16();
_latchedRegister = br.ReadInt32();
_sampleCycleTracker = br.ReadDouble();
_psgCycleTracker = br.ReadInt32();
for (int i = 0; i < 4; i++) { _counters[i] = br.ReadInt32(); _polarities[i] = br.ReadInt32(); }
_lfsr = br.ReadUInt16();
_previousSample = br.ReadSingle();
_previousFiltered = br.ReadSingle();
}
}
}
//using System;
//namespace Core.Audio
//{
// public class SmsApu
// {
// // The 8 internal registers of the PSG
// // 0: Tone 0 Frequency (10 bits)
// // 1: Tone 0 Volume (4 bits)
// // 2: Tone 1 Frequency (10 bits)
// // 3: Tone 1 Volume (4 bits)
// // 4: Tone 2 Frequency (10 bits)
// // 5: Tone 2 Volume (4 bits)
// // 6: Noise Control (3 bits)
// // 7: Noise Volume (4 bits)
// public ushort[] Registers { get; private set; } = new ushort[8];
// // Remembers which register the CPU is currently talking to
// private int _latchedRegister = 0;
// public SmsApu()
// {
// // Volumes default to 0x0F (Silence! 0 = max volume, 15 = off)
// Registers[1] = 0x0F;
// Registers[3] = 0x0F;
// Registers[5] = 0x0F;
// Registers[7] = 0x0F;
// }
// }
//}

27
Core/Cpu/Z80.cs
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@@ -1,4 +1,5 @@
using System;
using System.IO;
using Core.Interfaces;
using Core.Io;
@@ -97,6 +98,32 @@ namespace Core.Cpu
TotalTStates = 0;
}
public void SaveState(BinaryWriter bw)
{
bw.Write(TotalTStates);
bw.Write(InterruptMode);
bw.Write(IFF1);
bw.Write(IFF2);
bw.Write(InterruptRequested);
bw.Write(AF.Word); bw.Write(BC.Word); bw.Write(DE.Word); bw.Write(HL.Word);
bw.Write(AF_Prime.Word); bw.Write(BC_Prime.Word); bw.Write(DE_Prime.Word); bw.Write(HL_Prime.Word);
bw.Write(IX.Word); bw.Write(IY.Word);
bw.Write(PC); bw.Write(SP); bw.Write(I); bw.Write(R);
}
public void LoadState(BinaryReader br)
{
TotalTStates = br.ReadInt64();
InterruptMode = br.ReadInt32();
IFF1 = br.ReadBoolean();
IFF2 = br.ReadBoolean();
InterruptRequested = br.ReadBoolean();
AF.Word = br.ReadUInt16(); BC.Word = br.ReadUInt16(); DE.Word = br.ReadUInt16(); HL.Word = br.ReadUInt16();
AF_Prime.Word = br.ReadUInt16(); BC_Prime.Word = br.ReadUInt16(); DE_Prime.Word = br.ReadUInt16(); HL_Prime.Word = br.ReadUInt16();
IX.Word = br.ReadUInt16(); IY.Word = br.ReadUInt16();
PC = br.ReadUInt16(); SP = br.ReadUInt16(); I = br.ReadByte(); R = br.ReadByte();
}
private void ApplyWaitStates(ushort address)
{
// If a system (like a ULA) is attached and listening, ask it for the delay

23
Core/Memory/SmsMemoryBus.cs
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@@ -1,5 +1,6 @@
using Core.Interfaces;
using System;
using System.IO;
namespace Core.Memory
{
@@ -225,6 +226,28 @@ namespace Core.Memory
}
}
public void SaveState(BinaryWriter bw)
{
bw.Write(_workRam);
bw.Write(_cartridgeRam);
bw.Write(SramUsed);
bw.Write(_mapperControl);
bw.Write(_romBank0);
bw.Write(_romBank1);
bw.Write(_romBank2);
}
public void LoadState(BinaryReader br)
{
Array.Copy(br.ReadBytes(_workRam.Length), _workRam, _workRam.Length);
Array.Copy(br.ReadBytes(_cartridgeRam.Length), _cartridgeRam, _cartridgeRam.Length);
SramUsed = br.ReadBoolean();
_mapperControl = br.ReadByte();
_romBank0 = br.ReadInt32();
_romBank1 = br.ReadInt32();
_romBank2 = br.ReadInt32();
}
public void CleanRAMData()
{
Array.Clear(_workRam, 0, _workRam.Length);

25
Core/SmsMachine.cs
View File

@@ -73,5 +73,30 @@ namespace Core
}
}
}
public void SaveState(string filePath)
{
using (var fs = new System.IO.FileStream(filePath, System.IO.FileMode.Create))
using (var bw = new System.IO.BinaryWriter(fs))
{
Cpu.SaveState(bw);
MemoryBus.SaveState(bw);
VideoProcessor.SaveState(bw);
AudioProcessor.SaveState(bw);
}
}
public void LoadState(string filePath)
{
if (!System.IO.File.Exists(filePath)) return;
using (var fs = new System.IO.FileStream(filePath, System.IO.FileMode.Open))
using (var br = new System.IO.BinaryReader(fs))
{
Cpu.LoadState(br);
MemoryBus.LoadState(br);
VideoProcessor.LoadState(br);
AudioProcessor.LoadState(br);
}
}
}
}

75
Core/Video/SmsVdp.cs
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@@ -1,4 +1,5 @@
using System;
using System.IO;
namespace Core.Video
{
@@ -11,6 +12,10 @@ namespace Core.Video
public int[] FrameBuffer { get; private set; } = new int[256 * 192];
private bool[] _priorityBuffer = new bool[256 * 192]; // Tracks priority pixels!
// Hardware Latches
private int _latchedHScroll = 0;
private int _latchedVScroll = 0;
// The Control Port State Machine (Port 0xBF)
private bool _isSecondControlByte = false;
private ushort _controlWord = 0;
@@ -109,12 +114,20 @@ namespace Core.Video
{
_tStateCounter += tStates;
// 228 T-States per scanline
if (_tStateCounter >= 228)
{
_tStateCounter -= 228;
// --- MISSING LINE INTERRUPT COUNTDOWN ---
// 1. RENDER THE CURRENT LINE FIRST!
// The CPU just finished spending 228 cycles on this exact line.
// We draw it now using whatever scroll values the CPU set during that time.
if (_currentScanline < 192)
{
RenderScanline(_currentScanline);
}
// 2. CHECK LINE INTERRUPTS
// Now that the line is drawn, we check if we need to alert the CPU for the NEXT line.
if (_currentScanline <= 192)
{
_lineCounter--;
@@ -128,24 +141,21 @@ namespace Core.Video
{
_lineCounter = Registers[10]; // Reload outside active display
}
// ----------------------------------------
// 3. MOVE TO THE NEXT LINE
_currentScanline++;
if (_currentScanline < 192)
{
RenderScanline(_currentScanline);
}
else if (_currentScanline == 192)
{
_statusRegister |= 0x80; // Set VBlank Flag
}
// End of the NTSC frame (262 lines)
if (_currentScanline > 261)
{
_currentScanline = 0;
}
// 4. TRIGGER VBLANK
// The Master System sets the VBlank flag at the exact start of scanline 192.
if (_currentScanline == 192)
{
_statusRegister |= 0x80;
}
}
}
@@ -160,8 +170,8 @@ namespace Core.Video
// --- 1. RENDER BACKGROUND LINE ---
ushort nameTableBase = (ushort)((Registers[2] & 0x0E) << 10);
byte scrollX = Registers[8];
byte scrollY = Registers[9];
int scrollX = Registers[8];
int scrollY = Registers[9];
// THE FIX: The bits are now in the correct order!
bool lockColScroll = (Registers[0] & 0x80) != 0; // Bit 7: Locks right 8 columns (Fixes R-Type!)
@@ -303,5 +313,40 @@ namespace Core.Video
}
}
}
public void SaveState(BinaryWriter bw)
{
bw.Write(VRAM);
bw.Write(CRAM);
bw.Write(Registers);
bw.Write(_isSecondControlByte);
bw.Write(_controlWord);
bw.Write(_readBuffer);
bw.Write(_tStateCounter);
bw.Write(_currentScanline);
bw.Write(_lineCounter);
bw.Write(_statusRegister);
// ADD THESE:
bw.Write(_latchedHScroll);
bw.Write(_latchedVScroll);
}
public void LoadState(BinaryReader br)
{
Array.Copy(br.ReadBytes(VRAM.Length), VRAM, VRAM.Length);
Array.Copy(br.ReadBytes(CRAM.Length), CRAM, CRAM.Length);
Array.Copy(br.ReadBytes(Registers.Length), Registers, Registers.Length);
_isSecondControlByte = br.ReadBoolean();
_controlWord = br.ReadUInt16();
_readBuffer = br.ReadByte();
_tStateCounter = br.ReadInt32();
_currentScanline = br.ReadInt32();
_lineCounter = br.ReadInt32();
_statusRegister = br.ReadByte();
// ADD THESE:
_latchedHScroll = br.ReadInt32();
_latchedVScroll = br.ReadInt32();
}
}
}

2
Desktop/Desktop.csproj
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@@ -13,6 +13,8 @@
<PublishSingleFile>true</PublishSingleFile>
<IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
<RuntimeIdentifier>win-x64</RuntimeIdentifier>
<StartupObject>Desktop.Program</StartupObject>
<AssemblyName>Parsons Master System</AssemblyName>
</PropertyGroup>
<ItemGroup>

36
Desktop/Form1.Designer.cs generated
View File

@@ -36,11 +36,13 @@
exitToolStripMenuItem = new ToolStripMenuItem();
viewToolStripMenuItem = new ToolStripMenuItem();
debuggerToolStripMenuItem = new ToolStripMenuItem();
vRAMViewerToolStripMenuItem = new ToolStripMenuItem();
machineToolStripMenuItem = new ToolStripMenuItem();
resetToolStripMenuItem = new ToolStripMenuItem();
helpToolStripMenuItem = new ToolStripMenuItem();
aboutToolStripMenuItem = new ToolStripMenuItem();
vRAMViewerToolStripMenuItem = new ToolStripMenuItem();
saveStateToolStripMenuItem = new ToolStripMenuItem();
loadStateToolStripMenuItem = new ToolStripMenuItem();
menuStrip1.SuspendLayout();
SuspendLayout();
//
@@ -99,13 +101,20 @@
// debuggerToolStripMenuItem
//
debuggerToolStripMenuItem.Name = "debuggerToolStripMenuItem";
debuggerToolStripMenuItem.Size = new Size(270, 34);
debuggerToolStripMenuItem.Size = new Size(221, 34);
debuggerToolStripMenuItem.Text = "Debugger";
debuggerToolStripMenuItem.Click += debuggerToolStripMenuItem_Click;
//
// vRAMViewerToolStripMenuItem
//
vRAMViewerToolStripMenuItem.Name = "vRAMViewerToolStripMenuItem";
vRAMViewerToolStripMenuItem.Size = new Size(221, 34);
vRAMViewerToolStripMenuItem.Text = "VRAM Viewer";
vRAMViewerToolStripMenuItem.Click += vramViewerToolStripMenuItem_Click;
//
// machineToolStripMenuItem
//
machineToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { resetToolStripMenuItem });
machineToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { resetToolStripMenuItem, saveStateToolStripMenuItem, loadStateToolStripMenuItem });
machineToolStripMenuItem.Name = "machineToolStripMenuItem";
machineToolStripMenuItem.Size = new Size(94, 29);
machineToolStripMenuItem.Text = "Machine";
@@ -113,7 +122,7 @@
// resetToolStripMenuItem
//
resetToolStripMenuItem.Name = "resetToolStripMenuItem";
resetToolStripMenuItem.Size = new Size(156, 34);
resetToolStripMenuItem.Size = new Size(270, 34);
resetToolStripMenuItem.Text = "Reset";
resetToolStripMenuItem.Click += resetToolStripMenuItem_Click;
//
@@ -130,12 +139,19 @@
aboutToolStripMenuItem.Size = new Size(164, 34);
aboutToolStripMenuItem.Text = "About";
//
// vRAMViewerToolStripMenuItem
// saveStateToolStripMenuItem
//
vRAMViewerToolStripMenuItem.Name = "vRAMViewerToolStripMenuItem";
vRAMViewerToolStripMenuItem.Size = new Size(270, 34);
vRAMViewerToolStripMenuItem.Text = "VRAM Viewer";
vRAMViewerToolStripMenuItem.Click += vramViewerToolStripMenuItem_Click;
saveStateToolStripMenuItem.Name = "saveStateToolStripMenuItem";
saveStateToolStripMenuItem.Size = new Size(270, 34);
saveStateToolStripMenuItem.Text = "Save State";
saveStateToolStripMenuItem.Click += saveStateToolStripMenuItem_Click;
//
// loadStateToolStripMenuItem
//
loadStateToolStripMenuItem.Name = "loadStateToolStripMenuItem";
loadStateToolStripMenuItem.Size = new Size(270, 34);
loadStateToolStripMenuItem.Text = "Load State";
loadStateToolStripMenuItem.Click += loadStateToolStripMenuItem_Click;
//
// ParsonsForm1
//
@@ -168,5 +184,7 @@
private ToolStripMenuItem includedToolStripMenuItem;
private ToolStripMenuItem selectROMToolStripMenuItem1;
private ToolStripMenuItem vRAMViewerToolStripMenuItem;
private ToolStripMenuItem saveStateToolStripMenuItem;
private ToolStripMenuItem loadStateToolStripMenuItem;
}
}

109
Desktop/Form1.cs
View File

@@ -37,13 +37,8 @@ namespace Desktop
public ParsonsForm1()
{
InitializeComponent();
this.Text = $"Parsons Master System 2026 - {_currentRomName}";
_machine = new SmsMachine();
_audioPlayer = new NAudioPlayer();
_machine.AudioProcessor.AudioDevice = _audioPlayer;
PopulateIncludedRomsMenu();
// These are perfectly safe for the Visual Studio Designer!
this.KeyPreview = true;
this.KeyDown += Form1_KeyDown;
this.KeyUp += Form1_KeyUp;
@@ -51,6 +46,21 @@ namespace Desktop
this.ResizeRedraw = true;
}
// The Designer ignores this completely, but the compiled game runs it instantly!
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
this.Text = $"Parsons Master System - {_currentRomName}";
// Safe to initialize hardware and files here!
_machine = new SmsMachine();
_audioPlayer = new NAudioPlayer();
_machine.AudioProcessor.AudioDevice = _audioPlayer;
PopulateIncludedRomsMenu();
}
private void DrawScreen()
{
// Rapidly copy our VDP FrameBuffer into the Windows Bitmap
@@ -65,7 +75,8 @@ namespace Desktop
// Always call the base method so Windows can draw your MenuStrip!
base.OnPaint(e);
if (_screenBitmap != null)
// THE FIX: We MUST ensure the designer has actually built the menu strip before asking for its height!
if (_screenBitmap != null && menuStrip1 != null)
{
// 1. Set the rendering mode for perfect, chunky retro pixels!
e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
@@ -73,7 +84,7 @@ namespace Desktop
// 2. Calculate the drawing area.
// We start drawing BELOW the MenuStrip so it doesn't get covered up.
int topOffset = menuStrip1.Height; // Change 'menuStrip1' if your menu has a different (Name)
int topOffset = menuStrip1.Height;
Rectangle renderArea = new Rectangle(
0,
topOffset,
@@ -205,42 +216,37 @@ namespace Desktop
_currentRomName = Path.GetFileNameWithoutExtension(filePath);
this.Text = $"Parsons Master System - {_currentRomName}";
// 5. LOAD THE NEW SAVE DATA!
string savPath = Path.ChangeExtension(_currentRomPath, ".sav");
_machine.MemoryBus.LoadSaveData(savPath);
// 5. LOAD THE NEW SAVE DATA FROM THE EXE FOLDER!
string savPath = GetSaveFilePath();
if (savPath != null)
{
_machine.MemoryBus.LoadSaveData(savPath);
}
// 6. Turn the power on!
StartEmulator();
}
private string GetSaveFilePath()
{
// Don't try to save if a game hasn't been loaded yet!
if (string.IsNullOrEmpty(_currentRomName) || _currentRomName == "No ROM")
return null;
//private async void LoadRomAndStart(string filePath)
//{
// StopEmulator();
// if (_emulatorTask != null)
// {
// await _emulatorTask;
// }
// Application.StartupPath is the exact folder containing your .exe
string exeFolder = Application.StartupPath;
// // 2. Load the file
// byte[] rom = File.ReadAllBytes(filePath);
// // 3. Jam it into the Sega Mapper
// _machine.LoadCartridge(rom);
// _currentRomName = Path.GetFileNameWithoutExtension(filePath);
// this.Text = $"Parsons Master System - {_currentRomName}";
// // 5. Turn the power on!
// StartEmulator();
//}
// Combines the exe folder with "GameName.sav"
return Path.Combine(exeFolder, _currentRomName + ".sav");
}
private void SaveCurrentSram()
{
if (!string.IsNullOrEmpty(_currentRomPath) && _machine != null)
if (_machine != null)
{
// Swaps ".sms" for ".sav"
string savPath = Path.ChangeExtension(_currentRomPath, ".sav");
_machine.MemoryBus.SaveSaveData(savPath);
string savPath = GetSaveFilePath();
if (savPath != null)
{
_machine.MemoryBus.SaveSaveData(savPath);
}
}
}
@@ -361,5 +367,38 @@ namespace Desktop
SaveCurrentSram();
_audioPlayer?.Stop();
}
private async void saveStateToolStripMenuItem_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(_currentRomName) || _currentRomName == "No ROM") return;
// 1. Politely ask the emulator loop to pause, and wait for it to finish its current frame!
StopEmulator();
if (_emulatorTask != null) await _emulatorTask;
// 2. Change the extension to .state and save it right next to the .exe
string statePath = Path.ChangeExtension(GetSaveFilePath(), ".state");
_machine.SaveState(statePath);
// 3. Resume the emulator seamlessly
StartEmulator();
}
private async void loadStateToolStripMenuItem_Click(object sender, EventArgs e)
{
if (string.IsNullOrEmpty(_currentRomName) || _currentRomName == "No ROM") return;
string statePath = Path.ChangeExtension(GetSaveFilePath(), ".state");
if (!File.Exists(statePath)) return;
// 1. Pause the emulator
StopEmulator();
if (_emulatorTask != null) await _emulatorTask;
// 2. Inject the frozen state into the silicon!
_machine.LoadState(statePath);
// 3. Resume
StartEmulator();
}
}
}