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NESHawk - Mapper 204 - mask registers

This commit is contained in:
adelikat 2016-10-25 17:18:58 -05:00
parent 3e925a13a8
commit 933761c5c7
1 changed files with 8 additions and 3 deletions
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11
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/Mapper204.cs
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@ -9,6 +9,8 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
{
private int _reg1, _reg2;
private int prg_mask_16k, chr_mask_8k;
public override bool Configure(NES.EDetectionOrigin origin)
{
switch (Cart.board_type)
@ -19,6 +21,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
return false;
}
prg_mask_16k = Cart.prg_size / 16 - 1;
chr_mask_8k = Cart.chr_size / 8 - 1;
return true;
}
@ -42,17 +47,17 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
{
if (addr < 0x4000)
{
return ROM[(_reg2 * 0x4000) + (addr & 0x3FFF)];
return ROM[((_reg2 & prg_mask_16k) * 0x4000) + (addr & 0x3FFF)];
}
return ROM[(_reg1 * 0x4000) + (addr & 0x3FFF)];
return ROM[((_reg1 & prg_mask_16k) * 0x4000) + (addr & 0x3FFF)];
}
public override byte ReadPPU(int addr)
{
if (addr < 0x2000)
{
return VROM[(_reg2 * 0x2000) + (addr & 0x1FFF)];
return VROM[((_reg2 & chr_mask_8k) * 0x2000) + (addr & 0x1FFF)];
}
return base.ReadPPU(addr);