User:Blaziken257/T1 Music research

Some research on Telefang's music.

Reading music values

On overworld map

• Code is at 0x2E384.
• Music is based on the Denjuu's origin in any given acre, and the game maps the value of the origin to the value of the music:

Note: Check this more thoroughly.

Origin	Music
0x5	0x6
0x6	0x5
0x3	0x7
0xB	0x8
0xE	0x2A if you're in bottom-left quadrant in overworld, while in an antenna tree (i.e. 0xC904 in RAM == 0x06); 0x3 otherwise.
Everything else	0x3

In Denjuu battles

0x14620: Controls music in normal wild Denjuu battle.
0x14624: Appears to control music in T-Fanger battle. (Check this!)
0x14630: Appears to control music in boss battle. (Check this!)
0x14634: Appears to control music in Doomsday battle. (Check this!)

Sound Test

A mapping from external music IDs (i.e. visible IDs on the screen) to internal IDs are found starting at 0x12D3B in ROM. This corresponds with the first column in the music table below.

Finding music data in ROM

Since the music data is split up into multiple banks (each bank = 0x4000 bytes or 16 KB), a function exists at 0x15F5 to determine the bank and relative song ID.

If music ID < 0x10:
Don't change music ID, set bank to 0x20

Else if music ID < 0x20:
Subtract 0xF from music ID, set bank to 0x21

Else if music ID < 0x30:
Subtract 0x1F from music ID, set bank to 0x22

Else:
Subtract 0x2F from music ID, set bank to 0x23

New music ID is output to 0xFFA0 in RAM, bank (minus 0x20) is output to 0xCFF8 in RAM.

Music table

This is in the same order as the sound test, but is sometimes split apart for some reason. (Maybe more songs were planned?)

Internal ID	ROM Bank	Relative ID	Sound test	Song	Pointer
0x03	0x20	0x03	00	Overworld	0x82018
0x04		0x04	01	Cactos Ruins	0x82022
0x05		0x05	02	Ion Island	0x8202C
0x06		0x06	03	Barran	0x82036
0x07		0x07	04	Palm Sea	0x82040
0x08		0x08	05	Peperi Mts.	0x8204A
0x09		0x09	06	Toronko Spring	0x82054
0x0A		0x0A	07	Craft Research Center	0x8205E
0x0B		0x0B	08	Bryon Ruins	0x82068
0x12	0x21	0x03	09	Wild Denjuu screen	0x8601A
0x13		0x04	10	Before link battle	0x86024
0x14		0x05	11	Wild Denjuu battle	0x8602E
0x15		0x06	12	T-Fanger battle	0x86038
0x16		0x07	13	Boss/Mini-boss battle	0x86042
0x17		0x08	14	Doomsday battle	0x8604C
0x18		0x09	15	Battle win	0x86056
0x19		0x0A	16	Battle lose	0x86060
0x1A		0x0B	17	Level up	0x8606A
0x1B		0x0C	18	Game Over	0x86074
0x22	0x22	0x03	19	Kai	0x8A01A
0x23		0x04	20	Miyo	0x8A024
0x24		0x05	21	Shop	0x8A02E
0x25		0x06	22	Before battle	0x8A038
0x26		0x07	23	Nerikara	0x8A042
0x27		0x08	24	Multiplayer	0x8A04C
0x28		0x09	25	Got number	0x8A056
0x29		0x0A	26	To Denjuu World	0x8A060
0x2A		0x0B	27	Yarrow	0x8A06A
0x2B		0x0C	28	Natural evolution	0x8A074
0x2C		0x0D	29	Test evolution	0x8A07E
0x2D		0x0E	30	Experimental evolution	0x8A088
0x2E		0x0F	31	Lost phone number	0x8A09C
0x32	0x23	0x03	32	D-Shot menu	0x8E00E
0x33		0x04	33	Human World	0x8E018
0x34		0x05	34	Switch	0x8E022
0x35		0x06	35	Warp	0x8E02C
0x36		0x07	36	Title screen	0x8E040
0x37		0x08	37	Intro	0x8E036
0x38		0x09	38	Credits	0x8E04A
0x39		0x0A	39	Sanaeba	0x8E054
0x3B+		ID-0x2F	--	Glitchy sound	0x8E0FC (0x3B), 0x8E0FE (some others), etc.

Anything less than 0x3B that is not listed is silent. IT IS UNLIKELY THAT THERE IS UNUSED MUSIC IN THIS GAME (much to my dismay). Unless there are songs that have no pointers, which is possible but very unlikely (hey, I've seen it elsewhere).

There appears to be some code in the game that branches whether the relative music ID is 0x00 or 0x01, but it is not known what this does.

Each bank from 0x20 to 0x23 contains code to produce the music, and contains a pointer table. A bank 0x24 also exists and seems to contain the same code as the other four banks; however, this bank is never accessed from playing anything (music or sound effects) on the sound test. What could be in here?

For banks 0x20-0x23, the pointer table starts at 0x5FE2 in RAM (therefore, the ROM offsets for these pointer tables are 0x81FE2, 0x85FE2, 0x89FE2, and 0x8DFE2). For mystery bank 0x24, the pointer table starts at 0x7D2D in RAM (so the ROM offset for this table is 0x93D2D, which is just a string of 0x00's). The pointer table offsets can be changed at 0x4C1A in RAM (which corresponds to ROM offsets 0x80C1A, 0x84C1A, 0x88C1A, 0x8CC1A, and 0x90C1A). (Don't forget that in this game, like 99% of Game Boy games, the pointers are little endian!)

Unfortunately, even when changing the pointer table offset for bank 0x24, it still has glitchy music likely derived from garbage data.