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Old December 30th, 2012 (7:08 AM). Edited June 24th, 2013 by Jambo51.
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Jambo51 Jambo51 is offline
Glory To Arstotzka
     
    Join Date: Jun 2009
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    Posts: 732
    Hey there, Jambo51 here with another ASM/Hex editing combination tutorial.

    In Fire Red, you will surely have noticed, that apart from a few specific classes (Champion, Leader and Elite 4) there is absolutely no class based music for the trainer battles. Generally speaking, that is fine, since you don't want the average Youngsters etc to have special battle music, but what about Team Rocket? Shouldn't they have a special battle theme?

    What?!

    You can't do that with Fire Red?!

    I beg to differ! Follow this tutorial, and we'll have class based music in no time!

    So, firstly, assemble and insert this routine, and note down the location of your insert.

    Code:
    .text
    .align 2
    .thumb
    .thumb_func
    .global battlemusichack
    
    main:
    	ldr r0, there
    	ldr r1, [r0, #0x0]
    	mov r0, #0x80
    	lsl r0, r0, #0x5
    	and r0, r1
    	cmp r0, #0x0
    	bne later
    	mov r0, #0x80
    	lsl r0, r0, #0x7
    	and r0, r1
    	cmp r0, #0x0
    	bne later2
    	mov r0, #0x2
    	and r0, r1
    	cmp r0, #0x0
    	beq one
    later2:	mov r0, #0x85
    	lsl r0, r0, #0x1
    	b return2
    later:	mov r0, #0x95
    	lsl r0, r0, #0x1
    	b return2
    one:	mov r0, #0x8
    	and r1, r0
    	cmp r1, #0x0
    	beq wild
    	ldr r2, table
    	ldr r2, [r2, #0x0]
    	ldr r0, ramoffset
    	ldrh r1, [r0, #0x0]
    	lsl r0, r1, #0x2
    	add r0, r0, r1
    	lsl r0, r0, #0x3
    	add r0, r0, r2
    	ldrb r0, [r0, #0x1]
    	cmp r0, #0x54
    	beq gym
            cmp r0, #0x57
            beq gym
            cmp r0, #0x5A
            beq champ
    normal:	push {r2,r3}
    	ldr r3, terminate
    	ldr r1, classtable
    loop:	ldrh r2, [r1, #0x0]
    	cmp r2, r0
    	beq loadmusic
    	cmp r2, r3
    	beq carryon
    	add r1, #0x4
    	b loop
    carryon:	mov r0, #0x2
    	pop {r2,r3}
    	b return
    loadmusic:	ldrh r0, [r1, #0x2]
    	pop {r2,r3}
    	b return2
    wild:	ldr r0, there
    	ldr r0, [r0, #0x0]
    	mov r1, #0x1
    	and r0, r1
    	cmp r0, #0x0
    	bne alternate
    	mov r0, #0x0
    	b return
    alternate:	mov r0, #0x1
    	b return
    gym:	mov r0, #0x3
    	b return
    champ:	mov r0, #0x4
    return:	push {r2-r7}
    	mov r11, r0
    	ldr r0, variable
    	bl vardecrypt
    	ldrh r0, [r0, #0x0]
    	mov r1, #0xA
    	mul r0, r1
    	ldr r1, normaltable
    	add r0, r0, r1
    	mov r1, r11
    	lsl r1, r1, #0x1
            add r0, r0, r1
    	ldrh r0, [r0, #0x0]
    	mov r1, #0x0
    	mov r11, r1
    	pop {r2-r7}
    return2:	pop {r1}
    	bx r1
    vardecrypt:	ldr r1, vardec
    	bx r1
    .align
    table:		.word 0x08044028
    there:		.word 0x02022B4C
    ramoffset:	.word 0x020386AE
    terminate:	.word 0x0000FEFE
    classtable:	.word 0x08FDFDFD
    normaltable:	.word 0x08FEFEFE
    vardec:		.word 0x0806E455
    variable:	.word 0x000040F6
    Now, navigate to 0x43FF2 and change the code to 01 48 00 47 00 00 XX XX XX 08, where the XX's stand for your reversed pointer to the ASM you just inserted, plus 1 for THUMB mode, of course.

    Now, we're still not done, of course, so return to the location of the inserted ASM.

    Now, we must create a table which contains definitions for the class based music. This allows you to define as many EXTRA classes as you want, but you CANNOT change the music assigned to the Champion/Elite 4/Gym Leaders using this.

    So, in some aligned free space, create a table in this format:

    [Trainer Class - Byte][00 - Byte][Song to play - Half-Word]

    So, for example, I wanted the Team Rocket class to have track 0x130, I would put the following set of bytes into the table:

    Code:
    55 00 30 01
    You must do this for every class you wish to have custom music.

    When you're done with this, place:

    FE FE 00 00 at the end of the table, so in my example, it would be:

    Code:
    55 00 30 01 FE FE 00 00
    Easy, huh? Note down the location of this table and navigate to The ASM's insert location + 0xC0. Change the pointer here (should be FD FD FD 08) to point to the table you just created, NOT plus one.

    Now, for anyone who knows ASM, or is eagle eyed, you will have noticed it also contains a variable check. This variable check allows you to have regional music!

    Now, to create a set of regional music, navigate to some aligned free space, and start by putting the following set of values in:

    Code:
    2A 01 54 01 29 01 28 01 2B 01
    You may recognise these as the existing battle theme track numbers. If you don't intend to use regional music, you can move on from here straight to the changing the pointer later on.

    However, if you want regional music, you should follow the existing values with this format:

    [Wild Battle Track - Half-Word][Double Wild Battle Track - Half-Word][Trainer Battle Track - Half-Word][Gym Battle Track - Half-Word][Champion Battle Track - Half-Word]

    If you want any tracks to use the same values as their "normal" versions, you must set them to the same value. Eg, I want tracks 0x10A (wild), 0x140 (double wild), 0x109 (trainer), 0x154 (gym) but want to keep the Champion battle as 0x12B, then I would add the following values:

    Code:
    0A 01 40 01 09 01 54 01 2B 01
    When you're done adding new values, note down the start location of this table, and then navigate to the start of the ASM + 0xC4. The pointer here should be FE FE FE 08. Now you must change it to point to the new regional table you just created.

    Once you have done this, you are done!

    In terms of in game use, you don't have to do anything to get the class based music, it will immediately start working. For the regional music, you must set variable number 0x40F6 to the set of regional music you want to use.

    That is, for the "normal" set, set the variable to 0, and for any additional sets, set it to the correct number to pick that set. Everything else is handled in the background.
    __________________
    Hey guys, please check out my recreations of the gen 1 and 2 music on my custom engine at my SoundCloud! - Here!
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