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GB: Improve emulation of DMG-on-CGB register reads

This commit is contained in:
Vicki Pfau 2020-11-20 02:38:37 -08:00
parent d5e434c684
commit e050a2ae3d
3 changed files with 26 additions and 27 deletions
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53
src/gb/io.c
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@ -99,11 +99,12 @@ static const uint8_t _registerMask[] = {
[GB_REG_NR52] = 0x70, [GB_REG_NR52] = 0x70,
[GB_REG_STAT] = 0x80, [GB_REG_STAT] = 0x80,
[GB_REG_KEY1] = 0x7E, [GB_REG_KEY1] = 0x7E,
[GB_REG_VBK] = 0xFE, [GB_REG_VBK] = 0xFE,
[GB_REG_OCPS] = 0x40, [GB_REG_OCPS] = 0x40,
[GB_REG_BCPS] = 0x40, [GB_REG_BCPS] = 0x40,
[GB_REG_OPRI] = 0xFE, [GB_REG_OPRI] = 0xFE,
[GB_REG_SVBK] = 0xF8, [GB_REG_SVBK] = 0xF8,
[GB_REG_UNK75] = 0x8F,
[GB_REG_IE] = 0xE0, [GB_REG_IE] = 0xE0,
}; };
@ -531,11 +532,8 @@ void GBIOWrite(struct GB* gb, unsigned address, uint8_t value) {
goto success; goto success;
} }
failed: failed:
mLOG(GB_IO, STUB, "Writing to unknown register FF%02X:%02X", address, value); mLOG(GB_IO, GAME_ERROR, "Writing to unknown register FF%02X:%02X", address, value);
if (address >= GB_SIZE_IO) { return;
return;
}
break;
} }
success: success:
gb->memory.io[address] = value; gb->memory.io[address] = value;
@ -662,31 +660,32 @@ uint8_t GBIORead(struct GB* gb, unsigned address) {
case GB_REG_WX: case GB_REG_WX:
// Handled transparently by the registers // Handled transparently by the registers
break; break;
default: case GB_REG_KEY1:
if (gb->model >= GB_MODEL_CGB) { case GB_REG_VBK:
switch (address) { case GB_REG_HDMA1:
case GB_REG_KEY1: case GB_REG_HDMA2:
case GB_REG_VBK: case GB_REG_HDMA3:
case GB_REG_HDMA1: case GB_REG_HDMA4:
case GB_REG_HDMA2: case GB_REG_HDMA5:
case GB_REG_HDMA3: case GB_REG_BCPS:
case GB_REG_HDMA4: case GB_REG_BCPD:
case GB_REG_HDMA5: case GB_REG_OCPS:
case GB_REG_BCPS: case GB_REG_OCPD:
case GB_REG_BCPD: case GB_REG_SVBK:
case GB_REG_OCPS: case GB_REG_UNK72:
case GB_REG_OCPD: case GB_REG_UNK73:
case GB_REG_SVBK: case GB_REG_UNK75:
// Handled transparently by the registers // Handled transparently by the registers
goto success; if (gb->model < GB_MODEL_CGB) {
default: // In DMG mode, these all get initialized to 0xFF during reset
break; // But in DMG-on-CGB mode, they get initialized by the CGB reset so they can be non-zero
} mLOG(GB_IO, GAME_ERROR, "Reading from CGB register FF%02X in DMG mode", address);
} }
break;
default:
mLOG(GB_IO, STUB, "Reading from unknown register FF%02X", address); mLOG(GB_IO, STUB, "Reading from unknown register FF%02X", address);
return 0xFF; return 0xFF;
} }
success:
return gb->memory.io[address] | _registerMask[address]; return gb->memory.io[address] | _registerMask[address];
} }