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More Z80 cycle simplifications and fixes

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This commit is contained in:
Adrian Conlon
2025-08-03 21:55:24 +01:00
parent 6a32d0269d
commit 319190b7a5
1 changed files with 12 additions and 20 deletions
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Z80/Z80.cs
+12 -20
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@@ -82,6 +82,7 @@ namespace Z80
{
var displacement = (this._prefixDD ? this.IX : this.IY).Word + this._displacement;
this.MEMPTR.Word = (ushort)displacement;
this.Bus.Address.Assign(this.MEMPTR);
}
public void Exx() => this._registerSet ^= 1;
@@ -683,13 +684,13 @@ namespace Z80
#endregion
private void MemoryUpdate(int ticks = 0)
private void MemoryUpdate(int ticks)
{
this.OnWritingMemory();
try
{
using var _ = new AutoMREQ(this);
this.Tick(ticks);
using var _ = new AutoMREQ(this);
using var __ = new AutoWR(this);
this.Tick();
base.MemoryWrite();
@@ -711,9 +712,9 @@ namespace Z80
this.OnReadingMemory();
try
{
this.Tick();
try
{
this.Tick();
using var __ = new AutoMREQ(this);
using var _ = new AutoRD(this);
this.Tick();
@@ -984,7 +985,6 @@ namespace Z80
if (this._displaced)
{
this.DisplaceAddress();
this.Bus.Address.Assign(this.MEMPTR);
}
else
{
@@ -1058,7 +1058,7 @@ namespace Z80
{
this.Tick(2);
this.DisplaceAddress();
operand = this.MemoryRead(this.MEMPTR);
operand = this.MemoryRead();
}
else
{
@@ -2130,15 +2130,13 @@ namespace Z80
this.MEMPTR.Low = this.MemoryRead(this.SP);
this.Bus.Address.Increment();
this.MEMPTR.High = this.MemoryRead();
this.Tick(2);
this.Bus.Data = exchange.High;
exchange.High = this.MEMPTR.High;
this.MemoryUpdate();
this.Tick();
this.MemoryUpdate(2);
_ = this.Bus.Address.Decrement();
this.Bus.Data = exchange.Low;
exchange.Low = this.MEMPTR.Low;
this.MemoryUpdate();
this.MemoryUpdate(1);
this.Tick(2);
}
@@ -2227,8 +2225,7 @@ namespace Z80
{
this.MemoryRead(this.HL);
this.Bus.Address.Assign(this.DE);
this.Tick();
this.MemoryUpdate();
this.MemoryUpdate(1);
this.Tick(2);
var xy = this.A + this.Bus.Data;
this.SetBit(StatusBits.XF, xy & (int)Bits.Bit3);
@@ -2330,8 +2327,7 @@ namespace Z80
this.Bus.Address.Assign(this.BC);
this.ReadPort();
this.Bus.Address.Assign(this.HL);
this.Tick();
this.MemoryUpdate();
this.MemoryUpdate(1);
this.AdjustSZXY(--this.B);
this.SetBit(StatusBits.NF, this.Bus.Data & (byte)StatusBits.SF);
}
@@ -2492,10 +2488,8 @@ namespace Z80
private void RRD()
{
var memory = ReadMemoryIndirect(this.HL);
this.Tick(2);
this.Bus.Data = (byte)(PromoteNibble(this.A) | HighNibble(memory));
this.Tick(3);
this.MemoryUpdate();
this.MemoryUpdate(5);
this.A = (byte)(HigherNibble(this.A) | LowerNibble(memory));
this.AdjustSZPXY(this.A);
this.ClearBit(StatusBits.NF | StatusBits.HC);
@@ -2504,10 +2498,8 @@ namespace Z80
private void RLD()
{
var memory = ReadMemoryIndirect(this.HL);
this.Tick(2);
this.Bus.Data = (byte)(PromoteNibble(memory) | LowNibble(this.A));
this.Tick(3);
this.MemoryUpdate();
this.MemoryUpdate(5);
this.A = (byte)(HigherNibble(this.A) | HighNibble(memory));
this.AdjustSZPXY(this.A);
this.ClearBit(StatusBits.NF | StatusBits.HC);
@@ -2541,8 +2533,8 @@ namespace Z80
{
using var _ = new AutoIORQ(this);
using var __ = new AutoWR(this);
this.Ports.Write(this.Bus.Address, this.Bus.Data);
this.Tick();
this.Ports.Write(this.Bus.Address, this.Bus.Data);
}
this.Tick();
}