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Simplify LR35902 IO register access a little. 

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2019-08-12 18:34:17 +01:00
parent 583c5444a0
commit 3c7ca33efe
1 changed files with 20 additions and 13 deletions
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33
LR35902/IoRegisters.cs
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@ -100,11 +100,11 @@ namespace EightBit.GameBoy
public bool BootRomEnabled => !this.BootRomDisabled;
public int TimerClock => this.Peek((ushort)TAC) & (byte)Mask.Mask2;
public int TimerClock => this.TimerControl & (byte)Mask.Mask2;
public bool TimerEnabled => !this.TimerDisabled;
public bool TimerDisabled => (this.Peek((ushort)TAC) & (byte)Bits.Bit2) == 0;
public bool TimerDisabled => (this.TimerControl & (byte)Bits.Bit2) == 0;
public int TimerClockTicks
{
@ -126,10 +126,16 @@ namespace EightBit.GameBoy
}
}
private ref byte TimerControl => ref this.Reference(TAC);
private ref byte TimerModulo => ref this.Reference(TMA);
private ref byte TimerCounter => ref this.Reference(TIMA);
public void Reset()
{
this.Poke((ushort)NR52, 0xf1);
this.Poke((ushort)LCDC, (byte)(LcdcControl.DisplayBackground | LcdcControl.BackgroundCharacterDataSelection | LcdcControl.LcdEnable));
this.Poke(NR52, 0xf1);
this.Poke(LCDC, (byte)(LcdcControl.DisplayBackground | LcdcControl.BackgroundCharacterDataSelection | LcdcControl.LcdEnable));
this.divCounter.Word = 0xabcc;
this.timerCounter = 0;
}
@ -143,7 +149,7 @@ namespace EightBit.GameBoy
}
}
public void TriggerInterrupt(Interrupts cause) => this.Poke((ushort)IF, (byte)(this.Peek((ushort)IF) | (byte)cause));
public void TriggerInterrupt(Interrupts cause) => this.Reference(IF) |= (byte)cause;
public void CheckTimers(int cycles)
{
@ -154,29 +160,29 @@ namespace EightBit.GameBoy
public void IncrementDIV(int cycles)
{
this.divCounter.Word += (ushort)cycles;
this.Poke((ushort)DIV, this.divCounter.High);
this.Poke(DIV, this.divCounter.High);
}
public void IncrementTIMA()
{
var updated = this.Peek((ushort)TIMA) + 1;
var updated = this.TimerCounter + 1;
if ((updated & (int)Bits.Bit8) != 0)
{
this.TriggerInterrupt(Interrupts.TimerOverflow);
updated = this.Peek((ushort)TMA);
updated = this.TimerModulo;
}
this.Poke((ushort)TIMA, Chip.LowByte(updated));
this.TimerCounter = Chip.LowByte(updated);
}
public void IncrementLY() => this.Poke((ushort)LY, (byte)((this.Peek((ushort)LY) + 1) % GameBoy.Bus.TotalLineCount));
public void IncrementLY() => this.Poke(LY, (byte)((this.Peek(LY) + 1) % GameBoy.Bus.TotalLineCount));
public void ResetLY() => this.Poke((ushort)LY, 0);
public void ResetLY() => this.Poke(LY, 0);
public void UpdateLcdStatusMode(LcdStatusMode mode)
{
var current = this.Peek((ushort)STAT) & unchecked((byte)~Mask.Mask2);
this.Poke((ushort)STAT, (byte)(current | (int)mode));
var current = this.Peek(STAT) & unchecked((byte)~Mask.Mask2);
this.Poke(STAT, (byte)(current | (int)mode));
this.OnDisplayStatusModeUpdated(mode);
}
@ -289,6 +295,7 @@ namespace EightBit.GameBoy
this.timerCounter = this.divCounter.Word = 0;
break;
case TIMA: // R/W
break;
case TMA: // R/W
break;
case TAC: // R/W