6502/EightBitNet
1
0
Fork 0
mirror of https://github.com/MoleskiCoder/EightBitNet.git synced 2025-09-25 03:24:30 +00:00
Code Issues Projects Releases Wiki Activity

Isolate program counter increment/decrement (to be used for HALT processing)

Browse Source
This commit is contained in:
Adrian Conlon
2025-05-03 23:25:06 +01:00
parent 2501bdfd28
commit cbe871d365
6 changed files with 23 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
EightBit/Processor.cs
View File

@@ -220,10 +220,14 @@ namespace EightBit
protected virtual byte BusRead() => this.Bus.Read(); // N.B. Should be the only real call into the "Bus.Read" code.
protected virtual void IncrementPC() => ++this.PC.Word;
protected virtual void DecrementPC() => --this.PC.Word;
protected virtual byte FetchByte()
{
this.Bus.Address.Assign(this.PC);
this.PC.Word++;
IncrementPC();
return this.MemoryRead();
}

12
Intel8080/Intel8080.cs
View File

@@ -13,8 +13,6 @@ namespace Intel8080
: base(bus)
{
this.ports = ports;
this.LoweredHALT += this.Intel8080_LoweredHALT;
this.RaisedHALT += this.Intel8080_RaisedHALT;
}
private readonly Register16 af = new();
@@ -91,16 +89,6 @@ namespace Intel8080
}
}
private void Intel8080_RaisedHALT(object? sender, EventArgs e)
{
++this.PC.Word; // Release the PC from HALT instruction
}
private void Intel8080_LoweredHALT(object? sender, EventArgs e)
{
--this.PC.Word; // Keep the PC on the HALT instruction (i.e. executing NOP)
}
private int Sign()
{

1
LR35902/LR35902.cs
View File

@@ -669,7 +669,6 @@ namespace LR35902
{
this.LowerHALT(); // Exception (replaces LD (HL), (HL))
this.TickMachine(2);
//this.PC.Word++;
}
else
{

2
M6502/Core.cs
View File

@@ -664,7 +664,7 @@ namespace M6502
protected void ImmediateAddress()
{
this.Bus.Address.Assign(this.PC);
++this.PC.Word;
this.IncrementPC();
}
protected void AbsoluteAddress() => this.FetchWordAddress();

2
MC6809/MC6809.cs
View File

@@ -161,13 +161,11 @@ namespace EightBit
public void Halt()
{
--this.PC.Word;
this.LowerHALT();
}
public void Proceed()
{
++this.PC.Word;
this.RaiseHALT();
}

30
Z80/Z80.cs
View File

@@ -1021,9 +1021,9 @@ namespace Z80
case 6: // LDIR
if (this.LDIR())
{
--this.PC.Word;
this.DecrementPC();
this.MEMPTR.Assign(this.PC);
--this.PC.Word;
this.DecrementPC();
}
this.Tick(5);
@@ -1031,9 +1031,9 @@ namespace Z80
case 7: // LDDR
if (this.LDDR())
{
--this.PC.Word;
this.DecrementPC();
this.MEMPTR.Assign(this.PC);
--this.PC.Word;
this.DecrementPC();
}
this.Tick(5);
@@ -1055,9 +1055,9 @@ namespace Z80
case 6: // CPIR
if (this.CPIR())
{
--this.PC.Word;
this.DecrementPC();
this.MEMPTR.Assign(this.PC);
--this.PC.Word;
this.DecrementPC();
this.Tick(5);
}
@@ -1065,9 +1065,9 @@ namespace Z80
case 7: // CPDR
if (this.CPDR())
{
--this.PC.Word;
this.DecrementPC();
this.MEMPTR.Assign(this.PC);
--this.PC.Word;
this.DecrementPC();
this.Tick(3);
}
else
@@ -1094,7 +1094,8 @@ namespace Z80
case 6: // INIR
if (this.INIR())
{
this.PC.Word -= 2;
this.DecrementPC();
this.DecrementPC();
this.Tick(5);
}
@@ -1102,7 +1103,8 @@ namespace Z80
case 7: // INDR
if (this.INDR())
{
this.PC.Word -= 2;
this.DecrementPC();
this.DecrementPC();
this.Tick(5);
}
@@ -1124,7 +1126,8 @@ namespace Z80
case 6: // OTIR
if (this.OTIR())
{
this.PC.Word -= 2;
this.DecrementPC();
this.DecrementPC();
this.Tick(5);
}
@@ -1132,7 +1135,8 @@ namespace Z80
case 7: // OTDR
if (this.OTDR())
{
this.PC.Word -= 2;
this.DecrementPC();
this.DecrementPC();
this.Tick(5);
}
@@ -1664,7 +1668,7 @@ namespace Z80
private byte FetchInitialOpCode()
{
var returned = this.ReadInitialOpCode();
++this.PC.Word;
this.IncrementPC();
return returned;
}