From fbba7c25aed54efe1476278bf51ed805f483db70 Mon Sep 17 00:00:00 2001
From: Asnivor <coding@asnitech.co.uk>
Date: Mon, 11 Jun 2018 14:35:12 +0100
Subject: [PATCH] ZXHawk: New interrupt implementation
---
.../SinclairSpectrum/Machine/CPUMonitor.cs | 3 +
.../SinclairSpectrum/Machine/SpectrumBase.cs | 22 ++--
.../Computers/SinclairSpectrum/Machine/ULA.cs | 117 +++++++++---------
.../Machine/ZXSpectrum128K/ZX128.Screen.cs | 26 ++--
.../ZX128Plus2a.Screen.cs | 35 ++----
.../Machine/ZXSpectrum48K/ZX48.Screen.cs | 28 ++---
6 files changed, 104 insertions(+), 127 deletions(-)
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/CPUMonitor.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/CPUMonitor.cs
index 9b8a822c15..8838abe75e 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/CPUMonitor.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/CPUMonitor.cs
@@ -61,6 +61,9 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// </summary>
public void ExecuteCycle()
{
+ // simulate the ULA clock cycle before the CPU cycle
+ _machine.ULADevice.CycleClock(TotalExecutedCycles);
+
// is the next CPU cycle causing a BUSRQ or IORQ?
if (BUSRQ > 0)
{
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.cs
index 3b5eaa6da9..58753c45e5 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.cs
@@ -147,6 +147,9 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// </summary>
public virtual void ExecuteFrame(bool render, bool renderSound)
{
+ ULADevice.FrameEnd = false;
+ ULADevice.ULACycleCounter = CurrentFrameCycle;
+
InputRead = false;
_render = render;
_renderSound = renderSound;
@@ -164,15 +167,18 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
PollInput();
- while (CurrentFrameCycle < ULADevice.FrameLength)
+ for (;;)
{
- ULADevice.CheckForInterrupt(CurrentFrameCycle);
-
+ // run the CPU Monitor cycle
CPUMon.ExecuteCycle();
// cycle the tape device
if (UPDDiskDevice == null || !UPDDiskDevice.FDD_IsDiskLoaded)
TapeDevice.TapeCycle();
+
+ // has frame end been reached?
+ if (ULADevice.FrameEnd)
+ break;
}
OverFlow = (int)CurrentFrameCycle - ULADevice.FrameLength;
@@ -190,9 +196,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
AYDevice.EndFrame();
FrameCount++;
-
- // setup for next frame
- ULADevice.ResetInterrupt();
if (UPDDiskDevice == null || !UPDDiskDevice.FDD_IsDiskLoaded)
TapeDevice.EndFrame();
@@ -202,8 +205,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
// is this a lag frame?
Spectrum.IsLagFrame = !InputRead;
- // FDC debug
-
+ // FDC debug
if (UPDDiskDevice != null && UPDDiskDevice.writeDebug)
{
// only write UPD log every second
@@ -222,7 +224,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// </summary>
public virtual void HardReset()
{
- ULADevice.ResetInterrupt();
+ //ULADevice.ResetInterrupt();
ROMPaged = 0;
SpecialPagingMode = false;
RAMPaged = 0;
@@ -274,7 +276,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// </summary>
public virtual void SoftReset()
{
- ULADevice.ResetInterrupt();
+ //ULADevice.ResetInterrupt();
ROMPaged = 0;
SpecialPagingMode = false;
RAMPaged = 0;
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ULA.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ULA.cs
index e875a09565..2e9ff98b8c 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ULA.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ULA.cs
@@ -89,14 +89,9 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
public int InterruptLength;
/// <summary>
- /// Arbitrary offset into the contention array (for memory ops)
- /// </summary>
- public int MemoryContentionOffset;
-
- /// <summary>
- /// Arbitrary offset into the contention array (for port ops)
- /// </summary>
- public int PortContentionOffset;
+ /// Contention offset
+ /// </summary>
+ public int ContentionOffset;
/// <summary>
/// Arbitrary offset for render table generation
@@ -137,60 +132,58 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// </summary>
protected bool InterruptRaised;
- /// <summary>
- /// Signs that the interrupt signal has been revoked
- /// </summary>
- protected bool InterruptRevoked;
+ public long ULACycleCounter;
+ public long LastULATick;
+ public bool FrameEnd;
/// <summary>
- /// Resets the interrupt - this should happen every frame in order to raise
- /// the VBLANK interrupt in the proceding frame
- /// </summary>
- public virtual void ResetInterrupt()
- {
- InterruptRaised = false;
- InterruptRevoked = false;
- }
-
- /// <summary>
- /// Generates an interrupt in the current phase if needed
+ /// Cycles the ULA clock
+ /// Handles interrupt generation
/// </summary>
/// <param name="currentCycle"></param>
- public virtual void CheckForInterrupt(long currentCycle)
+ public virtual void CycleClock(long totalCycles)
{
- if (InterruptRevoked)
+ // has more than one cycle past since this last ran
+ // (this can be true if contention has taken place)
+ var ticksToProcess = totalCycles - LastULATick;
+
+ // store the current cycle
+ LastULATick = totalCycles;
+
+ // process the cycles past as well as the upcoming one
+ for (int i = 0; i < ticksToProcess; i++)
{
- // interrupt has already been handled
- return;
- }
+ ULACycleCounter++;
- if (currentCycle <= InterruptStartTime)
- {
- // interrupt does not need to be raised yet
- return;
- }
-
- if (currentCycle > InterruptStartTime + InterruptLength)
- {
- // interrupt should have already been raised and the cpu may or
- // may not have caught it. The time has passed so revoke the signal
- InterruptRevoked = true;
- _machine.CPU.FlagI = false;
- return;
- }
-
- if (InterruptRaised)
- {
- // INT is raised but not yet revoked
- // CPU has NOT handled it yet
- return;
- }
-
- // Raise the interrupt
- InterruptRaised = true;
- _machine.CPU.FlagI = true;
-
- CalcFlashCounter();
+ if (InterruptRaised)
+ {
+ // /INT pin is currently being held low
+ if (ULACycleCounter < InterruptLength + InterruptStartTime)
+ {
+ // ULA should still hold the /INT pin low
+ _machine.CPU.FlagI = true;
+ }
+ else
+ {
+ // its time (or past time) to stop holding the /INT pin low
+ _machine.CPU.FlagI = false;
+ InterruptRaised = false;
+ }
+ }
+ else
+ {
+ // interrupt is currently not raised
+ if (ULACycleCounter == FrameLength + InterruptStartTime)
+ {
+ // time to raise the interrupt
+ InterruptRaised = true;
+ _machine.CPU.FlagI = true;
+ FrameEnd = true;
+ ULACycleCounter = InterruptStartTime;
+ CalcFlashCounter();
+ }
+ }
+ }
}
/// <summary>
@@ -329,7 +322,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
{
for (var t = 0; t < _ula.FrameCycleLength; t++)
{
- var tStateScreen = t + _ula.RenderTableOffset + _ula.InterruptStartTime;
+ var tStateScreen = t + _ula.RenderTableOffset;// + _ula.InterruptStartTime;
if (tStateScreen < 0)
tStateScreen += _ula.FrameCycleLength;
@@ -460,7 +453,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
// calculate contention values
for (int t = 0; t < _ula.FrameCycleLength; t++)
{
- int shifted = t + _ula.RenderTableOffset + _ula.InterruptStartTime;
+ int shifted = t + _ula.RenderTableOffset + _ula.ContentionOffset; // _ula.InterruptStartTime;
if (shifted < 0)
shifted += _ula.FrameCycleLength;
shifted %= _ula.FrameCycleLength;
@@ -747,7 +740,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// <returns></returns>
public int GetContentionValue(int tstate)
{
- tstate += MemoryContentionOffset;
+ //tstate += MemoryContentionOffset;
if (tstate >= FrameCycleLength)
tstate -= FrameCycleLength;
@@ -763,7 +756,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
/// <returns></returns>
public int GetPortContentionValue(int tstate)
{
- tstate += PortContentionOffset;
+ //tstate += PortContentionOffset;
if (tstate >= FrameCycleLength)
tstate -= FrameCycleLength;
@@ -994,8 +987,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
ser.BeginSection("ULA");
if (ScreenBuffer != null)
ser.Sync("ScreenBuffer", ref ScreenBuffer, false);
- ser.Sync("FrameLength", ref FrameCycleLength);
- ser.Sync("ClockSpeed", ref ClockSpeed);
ser.Sync("BorderColor", ref BorderColor);
ser.Sync("LastTState", ref LastTState);
ser.Sync("flashOn", ref flashOn);
@@ -1010,6 +1001,10 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
ser.Sync("flash", ref flash);
ser.Sync("palPaper", ref palPaper);
ser.Sync("palInk", ref palInk);
+
+ ser.Sync("LastULATick", ref LastULATick);
+ ser.Sync("ULACycleCounter", ref ULACycleCounter);
+ ser.Sync("FrameEnd", ref FrameEnd);
ser.EndSection();
}
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128K/ZX128.Screen.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128K/ZX128.Screen.cs
index 54a0fe058f..06b1d7d9ba 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128K/ZX128.Screen.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128K/ZX128.Screen.cs
@@ -13,32 +13,28 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
public Screen128(SpectrumBase machine)
: base(machine)
{
+ // interrupt
+ InterruptStartTime = 3;
+ InterruptLength = 36;
+ // offsets
+ RenderTableOffset = 58;
+ ContentionOffset = 6;
+ FloatingBusOffset = 1;
// timing
ClockSpeed = 3546900;
FrameCycleLength = 70908;
- InterruptStartTime = 34;
- InterruptLength = 36;
ScanlineTime = 228;
-
- MemoryContentionOffset = 6;
- PortContentionOffset = 6;
- RenderTableOffset = -4;
- FloatingBusOffset = 1;
-
BorderLeftTime = 24;
BorderRightTime = 24;
-
FirstPaperLine = 63;
FirstPaperTState = 64;
-
- Border4T = true;
- Border4TStage = 2;
-
// screen layout
+ Border4T = true;
+ Border4TStage = 2;
ScreenWidth = 256;
ScreenHeight = 192;
- BorderTopHeight = 55; // 48;
- BorderBottomHeight = 56;
+ BorderTopHeight = 48; // 55; // 48;
+ BorderBottomHeight = 48; // 56;
BorderLeftWidth = 48;
BorderRightWidth = 48;
ScanLineWidth = BorderLeftWidth + ScreenWidth + BorderRightWidth;
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128KPlus2a/ZX128Plus2a.Screen.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128KPlus2a/ZX128Plus2a.Screen.cs
index 2611a7fd43..a95d06d8ce 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128KPlus2a/ZX128Plus2a.Screen.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum128KPlus2a/ZX128Plus2a.Screen.cs
@@ -13,43 +13,28 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
public Screen128Plus2a(SpectrumBase machine)
: base(machine)
{
+ // interrupt
+ InterruptStartTime = 0;
+ InterruptLength = 32;
+ // offsets
+ RenderTableOffset = 58;
+ ContentionOffset = 9;
+ FloatingBusOffset = 1;
// timing
ClockSpeed = 3546900;
FrameCycleLength = 70908;
- /*
- InterruptStartTime = 31;
- InterruptLength = 32;
ScanlineTime = 228;
-
- MemoryContentionOffset = 7;
- PortContentionOffset = 7;
- RenderTableOffset = 1;
- FloatingBusOffset = 1;
- */
-
- InterruptStartTime = 33;
- InterruptLength = 32;
- ScanlineTime = 228;
-
- MemoryContentionOffset = 6;
- PortContentionOffset = 6;
- RenderTableOffset = -2;
- FloatingBusOffset = 1;
-
BorderLeftTime = 24;
BorderRightTime = 24;
-
FirstPaperLine = 63;
FirstPaperTState = 64;
-
+ // screen layout
Border4T = true;
Border4TStage = 2;
-
- // screen layout
ScreenWidth = 256;
ScreenHeight = 192;
- BorderTopHeight = 55;
- BorderBottomHeight = 56;
+ BorderTopHeight = 48;// 55;
+ BorderBottomHeight = 48; // 56;
BorderLeftWidth = 48;
BorderRightWidth = 48;
ScanLineWidth = BorderLeftWidth + ScreenWidth + BorderRightWidth;
diff --git a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum48K/ZX48.Screen.cs b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum48K/ZX48.Screen.cs
index 0a4c236d86..d572f44e37 100644
--- a/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum48K/ZX48.Screen.cs
+++ b/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/ZXSpectrum48K/ZX48.Screen.cs
@@ -13,32 +13,28 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
public Screen48(SpectrumBase machine)
: base(machine)
{
- // timing
- ClockSpeed = 3500000;
- FrameCycleLength = 69888;
- InterruptStartTime = 33;
+ // interrupt
+ InterruptStartTime = 3;
InterruptLength = 32;
+ // offsets
+ RenderTableOffset = 56;
+ ContentionOffset = 6;
+ FloatingBusOffset = 1;
+ // timing
+ ClockSpeed = 3500000;
+ FrameCycleLength = 69888;
ScanlineTime = 224;
-
- MemoryContentionOffset = 6;
- PortContentionOffset = 6;
- RenderTableOffset = -9; // 2;
- FloatingBusOffset = 1;
-
BorderLeftTime = 24;
BorderRightTime = 24;
-
FirstPaperLine = 64;
FirstPaperTState = 64;
-
+ // screen layout
Border4T = true;
Border4TStage = 0;
-
- // screen layout
ScreenWidth = 256;
ScreenHeight = 192;
- BorderTopHeight = 55;// 48;
- BorderBottomHeight = 56;
+ BorderTopHeight = 48;// 55;// 48;
+ BorderBottomHeight = 48;// 56;
BorderLeftWidth = 48;
BorderRightWidth = 48;
ScanLineWidth = BorderLeftWidth + ScreenWidth + BorderRightWidth;