/// <summary>
/// PPUが持つVRAMへデータを書き込む。
/// </summary>
/// <param name="data"></param>
private void WriteVideoRamData(byte data)
{
if (currentVideoRamAddress >= 0x2000)
{
if (0x3f00 <= currentVideoRamAddress && currentVideoRamAddress < 0x4000)
{
// パレットテーブルへの書き込み
var address = (Address)(currentVideoRamAddress & 0x1F);
paletteRam.Write(address, data);
}
else
{
// ネームテーブル、属性テーブルへの書き込み
// 0x3000 - 0x3EFF間のミラーリングを考慮
var address = 0x3000 <= currentVideoRamAddress && currentVideoRamAddress < 0x3F00
? (Address)(currentVideoRamAddress - 0x3000)
: (Address)(currentVideoRamAddress - 0x2000);
videoRam.Write(address, data);
}
}
else
{
// TODO キャラクタRAMへの書き込み
}
currentVideoRamAddress += controlRegister.AddressIncrement;
}
public void Write(Address address, byte data)
{
switch (address & 0xE000)
{
case 0x0000:
// WRAM
wram.Write(address, data);
return;
case 0x2000:
// PPU
ppu.Write(address, data);
return;
case 0x4000:
// APU, Controller I/O
return;
case 0x6000:
return;
case 0x8000:
case 0xC000:
// Program RAM?
return;
default:
throw new ArgumentException("Trying to access an address not included in the specification.");
}
}
/// <summary>
/// スプライトRAMにデータを書き込む。
/// </summary>
/// <param name="data"></param>
private void WriteSpriteRamData(byte data)
{
spriteRam.Write(currentVideoRamAddress, data);
currentVideoRamAddress += 0x01;
}