Map Script Format

When the game loads a map it looks at a pointer table at 0x06959C and runs a some kind of script to load the map parts.

There seem to be 1314(check) entries.

This code below is used to convert the ROM to a RAM address.

i.e. when loading map id 0 the first offset is 0x83FF05 which after the code is run turns into 0xA5FF83 (0x25FF83 ROM).

u32 Background::GetAddress()
{ 
	u32 AdrLow = GetBytei(); 
	u16 AdrHigh = GetWordi();

	u8 push = AdrHigh & 0x7F;
	
	AdrHigh = push ^ AdrHigh;
	AdrHigh<<= 1;
	AdrHigh |= 0x80;
	AdrHigh |= push;
	AdrHigh += (((ROMOffset|(1<<23)) & 0xFF0000) >> 8);

	if( (AdrHigh & 0xFF00) >= 0xC000 )
		AdrHigh &= 0xFF7F;
	
	return (AdrHigh<<8)|AdrLow;
}

Map script #0

This map script is used to select a song to be played by the 08 FC command

Commands

Opcode	Argument length (byte)	Function
0x00	2	Run map script Offset Length (Byte) Name 0 2 Map ID
0x02	5	Play SPC data Offset Length (Byte) Name 0 1 Unknown 1 1 Track ID 2 3 SPC data Offset
0x04	5	Load background using 2Bit format. Only used by map ID 0x106. Offset Length (Byte) Name 0 3 Offset 3 1 Unknown 4 1 Layer
0x08	variable	Run sub command Opcode Argument length (byte) Function 0xF8 1 Return from sub function 0xF9 2 Call map script 0xFA 2 Push map script address 0xFC 2 Calls map script #0 which then plays the selected song id 0xFD 4 Call map script when flag is true 0xFE 2 Return from script 0xFF 0 End of script
0x10	4	Load map data Offset Length (Byte) Name 0 1 0x01 - Map layer 0 0x02 - Map layer 1 1 3 Address
0x20	7	Load collision data or tile maps Offset Length (Byte) Name 0 1 Seek 1 1 Size 2 1 Offset 3 1 Layer ID 0x80 set 0x80 clear Collision data Map tiles 4 3 Address
0x40	6	Load palette Offset Length (Byte) Name 0 1 Pal index 1 1 Pal size 2 1 Pal offset 3 3 Address
0x80	9	Load tile data Offset Length (Byte) Name 0 1 Seek 1 1 Size 2 1 Tile mode 3 3 Address 6 2 Bank 7 1 Unknown