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Simplfy interrupts on Z80

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This commit is contained in:
Adrian Conlon
2025-08-07 19:05:41 +01:00
parent d332c57e47
commit 41be64ad99
2 changed files with 43 additions and 19 deletions
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Z80/Z80.cs
+29 -15
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@@ -472,6 +472,16 @@ namespace Z80
this.MemoryUpdate(1);
}
private void RefreshMemory()
{
this.Bus.Address.Assign(this.REFRESH, this.IV);
this.LowerRFSH();
this.Tick();
this.LowerMREQ();
this.RaiseMREQ();
this.RaiseRFSH();
}
protected override byte MemoryRead()
{
this.OnReadingMemory();
@@ -484,12 +494,7 @@ namespace Z80
this.RaiseMREQ();
if (this.M1.Lowered())
{
this.Bus.Address.Assign(this.REFRESH, this.IV);
this.LowerRFSH();
this.Tick();
this.LowerMREQ();
this.RaiseMREQ();
this.RaiseRFSH();
this.RefreshMemory();
}
this.Tick();
this.OnReadMemory();
@@ -518,10 +523,16 @@ namespace Z80
private byte ReadDataUnderInterrupt()
{
this.LowerM1();
this.Tick(2);
this.LowerIORQ();
this.Tick();
var data = this.Bus.Data;
this.Tick();
this.RaiseIORQ();
this.RaiseM1();
return this.Bus.Data;
this.Tick();
this.RefreshMemory();
return data;
}
protected override void HandleINT()
@@ -530,8 +541,6 @@ namespace Z80
var data = this.ReadDataUnderInterrupt();
this.DisableInterrupts();
this.Tick(5);
switch (this.IM)
{
case 0: // i8080 equivalent
@@ -542,9 +551,9 @@ namespace Z80
this.Restart(7 << 3); // 7 cycles
break;
case 2:
this.Tick(7);
this.Tick();
this.MEMPTR.Assign(data, this.IV);
this.Call(this.MEMPTR);
this.Call();
break;
default:
throw new NotSupportedException("Invalid interrupt mode");
@@ -701,9 +710,15 @@ namespace Z80
private static byte SET(int n, byte operand) => SetBit(operand, Bit(n));
protected override void DisableInterrupts() => this.IFF1 = this.IFF2 = false;
protected override void DisableInterrupts()
{
this.IFF1 = this.IFF2 = false;
}
protected override void EnableInterrupts() => this.IFF1 = this.IFF2 = true;
protected override void EnableInterrupts()
{
this.IFF1 = this.IFF2 = true;
}
private Register16 HL2() => this._prefixDD ? this.IX : this._prefixFD ? this.IY : this.HL;
@@ -1547,10 +1562,9 @@ namespace Z80
private void HandleNMI()
{
this.IFF1 = false;
this.RaiseNMI();
this.RaiseHALT();
this.IFF2 = this.IFF1;
this.IFF1 = false;
this.LowerM1();
_ = this.Bus.Data;
this.RaiseM1();