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Step can be split a little to make it easier to override.

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This commit is contained in:
Adrian Conlon
2024-07-24 17:21:49 +01:00
parent e746f218e3
commit c8ac0f20dc
8 changed files with 308 additions and 228 deletions
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LR35902/LR35902.cs
+32 -47
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@@ -15,10 +15,6 @@ namespace EightBit.GameBoy
public LR35902(Bus bus)
: base(bus) => this.bus = bus;
public event EventHandler<EventArgs> ExecutingInstruction;
public event EventHandler<EventArgs> ExecutedInstruction;
public int ClockCycles => this.Cycles * 4;
public override Register16 AF
@@ -63,61 +59,50 @@ namespace EightBit.GameBoy
System.Diagnostics.Debug.Assert(this.Cycles > 0, $"No timing associated with instruction (CB prefixed? {this.prefixCB}) 0x{this.OpCode:X2}");
}
public override int Step()
public override void PoweredStep()
{
this.OnExecutingInstruction();
this.prefixCB = false;
this.ResetCycles();
if (this.Powered)
var interruptEnable = this.Bus.Peek(IoRegisters.BASE + IoRegisters.IE);
var interruptFlags = this.bus.IO.Peek(IoRegisters.IF);
var masked = interruptEnable & interruptFlags;
if (masked != 0)
{
var interruptEnable = this.Bus.Peek(IoRegisters.BASE + IoRegisters.IE);
var interruptFlags = this.bus.IO.Peek(IoRegisters.IF);
var masked = interruptEnable & interruptFlags;
if (masked != 0)
if (this.IME)
{
if (this.IME)
{
this.bus.IO.Poke(IoRegisters.IF, 0);
this.LowerINT();
var index = Chip.FindFirstSet(masked);
this.Bus.Data = (byte)(0x38 + (index << 3));
}
else
{
this.RaiseHALT();
}
}
if (this.RESET.Lowered())
{
this.HandleRESET();
}
else if (this.INT.Lowered())
{
this.HandleINT();
}
else if (this.HALT.Lowered())
{
this.Execute(0); // NOP
this.bus.IO.Poke(IoRegisters.IF, 0);
this.LowerINT();
var index = Chip.FindFirstSet(masked);
this.Bus.Data = (byte)(0x38 + (index << 3));
}
else
{
this.Execute(this.FetchByte());
this.RaiseHALT();
}
this.bus.IO.CheckTimers(this.ClockCycles);
this.bus.IO.TransferDma();
}
this.OnExecutedInstruction();
return this.ClockCycles;
if (this.RESET.Lowered())
{
this.HandleRESET();
}
else if (this.INT.Lowered())
{
this.HandleINT();
}
else if (this.HALT.Lowered())
{
this.Execute(0); // NOP
}
else
{
this.Execute(this.FetchByte());
}
this.bus.IO.CheckTimers(this.ClockCycles);
this.bus.IO.TransferDma();
}
protected virtual void OnExecutingInstruction() => this.ExecutingInstruction?.Invoke(this, EventArgs.Empty);
protected virtual void OnExecutedInstruction() => this.ExecutedInstruction?.Invoke(this, EventArgs.Empty);
protected override void HandleRESET()
{
base.HandleRESET();