There are a few bugs I have noticed. One is that the spindash sound will not raise pitch. The music is not a perfect adaptation of Sonic 2's music, particularly sometimes the PSG channels sound slightly different. This is most noticable in Emerald Hill's music. Besides this, there are no problems. If the above bugs will not bother you too badly, then you'll like using the Sonic 2 Clone Driver after working with Sonic 2's own sound driver. The Clone Driver is much easier to port music to, and in fact, Sonic 1 music can even just be bincluded into the ROM. This is because it's based on the Sonic 1 sound driver, and uses similar (if not the same) formatting. With this out of the way, now it's time to edit the Sonic 2 HG Dissasembly! Step 1 - getting started --------------------------------------------------------------------------------------------------------------------------------------------------------------- Back up your dissasembly if you haven't already. To start, go into your sound folder, where you'll have a DAC folder, a music folder, and a PCM folder. DELETE THEM ALL! and then extract "Sonic 2 Clone Driver_fixed.7z" into the main folder of your dissasembly. And then open up s2.sounddriver.asm, we're going to delete a lot of data from it. Find zMasterPlaylist and delete the following lines: Code (Text): ; zbyte_11F5h: zMasterPlaylist: ; Music IDs offset := MusicPoint2 ptrsize := 2 idstart := 80h ; note: +20h means uncompressed, here ; +40h is an (ignored) flag, possibly to force PAL mode on/off zMusIDPtr_2PResult: db id(MusPtr_2PResult) ; 92 zMusIDPtr_EHZ: db id(MusPtr_EHZ) ; 81 zMusIDPtr_MCZ_2P: db id(MusPtr_MCZ_2P) ; 85 zMusIDPtr_OOZ: db id(MusPtr_OOZ) ; 8F zMusIDPtr_MTZ: db id(MusPtr_MTZ) ; 82 zMusIDPtr_HTZ: db id(MusPtr_HTZ) ; 94 zMusIDPtr_ARZ: db id(MusPtr_ARZ) ; 86 zMusIDPtr_CNZ_2P: db id(MusPtr_CNZ_2P) ; 80 zMusIDPtr_CNZ: db id(MusPtr_CNZ) ; 83 zMusIDPtr_DEZ: db id(MusPtr_DEZ) ; 87 zMusIDPtr_MCZ: db id(MusPtr_MCZ) ; 84 zMusIDPtr_EHZ_2P: db id(MusPtr_EHZ_2P) ; 91 zMusIDPtr_SCZ: db id(MusPtr_SCZ) ; 8E zMusIDPtr_CPZ: db id(MusPtr_CPZ) ; 8C zMusIDPtr_WFZ: db id(MusPtr_WFZ) ; 90 zMusIDPtr_HPZ: db id(MusPtr_HPZ) ; 9B zMusIDPtr_Options: db id(MusPtr_Options) ; 89 zMusIDPtr_SpecStage: db id(MusPtr_SpecStage) ; 88 zMusIDPtr_Boss: db id(MusPtr_Boss) ; 8D zMusIDPtr_EndBoss: db id(MusPtr_EndBoss) ; 8B zMusIDPtr_Ending: db id(MusPtr_Ending) ; 8A zMusIDPtr_SuperSonic: db id(MusPtr_SuperSonic) ; 93 zMusIDPtr_Invincible: db id(MusPtr_Invincible) ; 99 zMusIDPtr_ExtraLife: db id(MusPtr_ExtraLife)+20h; B5 zMusIDPtr_Title: db id(MusPtr_Title) ; 96 zMusIDPtr_EndLevel: db id(MusPtr_EndLevel) ; 97 zMusIDPtr_GameOver: db id(MusPtr_GameOver)+20h ; B8 zMusIDPtr_Continue: db (MusPtr_Continue-MusicPoint1)/ptrsize ; 0 zMusIDPtr_Emerald: db id(MusPtr_Emerald)+20h ; BA zMusIDPtr_Credits: db id(MusPtr_Credits)+20h ; BD zMusIDPtr_Countdown: db id(MusPtr_Drowning)+40h ; DC zMusIDPtr__End: Then go to zDACMasterPlaylist, and delete these: Code (Text): db id(zDACPtr_Sample1),17h ; 81h db id(zDACPtr_Sample2),1 ; 82h db id(zDACPtr_Sample3),6 ; 83h db id(zDACPtr_Sample4),8 ; 84h db id(zDACPtr_Sample5),1Bh ; 85h db id(zDACPtr_Sample6),0Ah ; 86h db id(zDACPtr_Sample7),1Bh ; 87h db id(zDACPtr_Sample5),12h ; 88h db id(zDACPtr_Sample5),15h ; 89h db id(zDACPtr_Sample5),1Ch ; 8Ah db id(zDACPtr_Sample5),1Dh ; 8Bh db id(zDACPtr_Sample6),2 ; 8Ch db id(zDACPtr_Sample6),5 ; 8Dh db id(zDACPtr_Sample6),8 ; 8Eh db id(zDACPtr_Sample7),8 ; 8Fh db id(zDACPtr_Sample7),0Bh ; 90h db id(zDACPtr_Sample7),12h ; 91h Step 2 - Deleting broken references --------------------------------------------------------------------------------------------------------------------------------------------------------------- Now open up s2.asm, and search for the line "; end of 'ROM'" near the end of your dissasemby. On the empty line before it, past this: Code (Text): include "Sonic 2 Clone Driver.asm" even After this, search for "SoundIndex:", and delete everything for it, up to and including "SndPtr__End:" Now there are many unused sounds, Sound20 - Sound70 in the dissasembly that will be unused. If you wish, delete those too, as they will only take space. Once you've done that, locate "MusicPoint2:", and delete that, and everything below it it until the following line: Code (Text): if * > soundBankStart + $8000 Leave this line and everything below it alone for the time being. Now find the line Code (Text): ; loc_F1E8C: Below this line is where the Sega sound is included. If we delete it, we will get errors. If we leave I, we will get errors. So what do we do? Change it! Replace this: Code (Text): ; ------------------------------------------------------------------------------- ; Sega Intro Sound ; 8-bit unsigned raw audio at 16Khz ; ------------------------------------------------------------------------------- ; loc_F1E8C: Snd_Sega: BINCLUDE "sound/PCM/SEGA.bin" Snd_Sega_End: if Snd_Sega_End - Snd_Sega > $8000 fatal "Sega sound must fit within $8000 bytes, but you have a $\{Snd_Sega_End-Snd_Sega} byte Sega sound." endif if Snd_Sega_End - Snd_Sega > Size_of_SEGA_sound fatal "Size_of_SEGA_sound = $\{Size_of_SEGA_sound}, but you have a $\{Snd_Sega_End-Snd_Sega} byte Sega sound." endif With this: Code (Text): ; loc_F1E8C: Snd_Sega: rts Snd_Sega_End: Now, we need to delete the old BINCLUDEd DAC samples. Got to loc_ED100, or SndDAC_Start. Staring at line "; loc_ED100:", delete everything down to (But not including) this chunk of code. Code (Text): ; -------------------------------------------------------------------- ; Nemesis compressed art (20 blocks) ; Buzzer's fireball ArtNem_Buzzer_Fireball: BINCLUDE "art/nemesis/Fireball 1 (Buzzer).bin" ; -------------------------------------------------------------------- That is art used in the game, so obviously we don't want that to get deleted. Right above if, you will also see this line: Code (Text): cnop -Size_of_DAC_samples, $8000 You need to delete that too. Finally, search for sub_EC000, or "SoundDriverLoad", which will look like this: Code (Text): ; --------------------------------------------------------------------------- ; Subroutine to load the sound driver ; --------------------------------------------------------------------------- ; sub_EC000: SoundDriverLoad: move sr,-(sp) movem.l d0-a6,-(sp) move #$2700,sr lea (Z80_Bus_Request).l,a3 lea (Z80_Reset).l,a2 moveq #0,d2 move.w #$100,d1 move.w d1,(a3) ; get Z80 bus move.w d1,(a2) ; release Z80 reset (was held high by console on startup) - btst d2,(a3) bne.s - ; wait until the 68000 has the bus jsr DecompressSoundDriver(pc) btst #0,(VDP_control_port+1).l ; check video mode sne (Z80_RAM+zPalModeByte).l ; set if PAL move.w d2,(a2) ; hold Z80 reset move.w d2,(a3) ; release Z80 bus moveq #$E6,d0 - dbf d0,- ; wait for 2,314 cycles move.w d1,(a2) ; release Z80 reset movem.l (sp)+,d0-a6 move (sp)+,sr rts Delete the whole thing, as it will now do nothing but cause an error. Step 3 - Replace a bunch of stuff. --------------------------------------------------------------------------------------------------------------------------------------------------------------- Search for the routine VintRet (Search for "VintRet:"), and you'll have something like this: Code (Text): VintRet: addq.l #1,(Vint_runcount).w movem.l (sp)+,d0-a6 rte Replace it with this: Code (Text): VintRet: jsr Init_Sonic1_Sound_Driver ; init Sonic 1 sound driver addq.l #1,(Vint_runcount).w movem.l (sp)+,d0-a6 rte Next, go to JmpTo_SoundDriverLoad, and find all of this: Code (Text): JmpTo_SoundDriverLoad nop jmp (SoundDriverLoad).l ; End of function JmpTo_SoundDriverLoad ; =========================================================================== ; unused mostly-leftover subroutine to load the sound driver ; SoundDriverLoadS1: move.w #$100,(Z80_Bus_Request).l ; stop the Z80 move.w #$100,(Z80_Reset).l; reset the Z80 lea (Z80_RAM).l,a1 move.b #$F3,(a1)+ move.b #$F3,(a1)+ move.b #$C3,(a1)+ move.b #0,(a1)+ move.b #0,(a1)+ move.w #0,(Z80_Reset).l nop nop nop nop move.w #$100,(Z80_Reset).l ; reset the Z80 move.w #0,(Z80_Bus_Request).l ; start the Z80 rts and replace it like this: Code (Text): JmpTo_SoundDriverLoad move.w #$100,(Z80_Bus_Request).l ; stop the Z80 move.w #$100,(Z80_Reset).l ; reset the Z80 lea (Kos_Z80).l,a0 lea (Z80_RAM).l,a1 bsr.w KosDec move.b #$F3,(a1)+ move.b #$F3,(a1)+ move.b #$C3,(a1)+ move.b #0,(a1)+ move.b #0,(a1)+ move.w #0,(Z80_Reset).l nop nop nop nop move.w #$100,(Z80_Reset).l ; reset the Z80 move.w #0,(Z80_Bus_Request).l ; start the Z80 rts Next, find PlayMusic, which should look like this this: Code (Text): ; sub_135E: PlayMusic: tst.b (Music_to_play).w bne.s + move.b d0,(Music_to_play).w rts + move.b d0,(Music_to_play_2).w rts ; End of function PlayMusic And replace it with this: Code (Text): ; sub_135E: PlayMusic: ; tst.b ($FFFFFFE0).w ; bne.s + ; move.b d0,($FFFFFFE0).w move.b d0,($FFFFF00A).w rts + move.b d0,($FFFFF00A).w rts ; End of function PlayMusic Right beneath that should be PlaySound. Replace PlaySound with this: Code (Text): ; sub_1370 PlaySound: move.b d0,($FFFFF00B).w rts ; End of function PlaySound Now we need to change PlaySoundStereo, which should be right beath PlaySound. Replace it with this: Code (Text): ; sub_1376: PlaySoundStereo: bra.s PlayMusic ; skip over routine (For S1 driver) move.b d0,(SFX_to_play_2).w rts ; End of function PlaySoundStereo Now PlaySoundLocal is the next thing to edit, and again, it should be right below PlaySoundStereo. Replace it with this: Code (Text): ; sub_137C: PlaySoundLocal: tst.b render_flags(a0) bpl.s + move.b d0,($FFFFF00B).w + rts Below this is the routine PauseGame. Rather than replacing that entire routine, we are simply going to find this: Code (Text): + move.w #1,(Game_paused).w ; freeze time move.b #MusID_Pause,(Music_to_play).w ; pause music And replace it with this: Code (Text): + move.w #1,(Game_paused).w ; freeze time move.b #1,($FFFFF003).w ; pause music Now go to Pause_Resume, which should look like this: Code (Text): ; loc_13F2: Pause_Resume: move.b #MusID_Unpause,(Music_to_play).w Replace it with this: Code (Text): ; loc_13F2: Pause_Resume: move.b #$80,($FFFFF003).w Now, find Pause_SlowMo, which should be this: Code (Text): ; loc_1400: Pause_SlowMo: move.w #1,(Game_paused).w move.b #MusID_Unpause,(Music_to_play).w rts Replace it with the following: Code (Text): ; loc_1400: Pause_SlowMo: move.w #1,(Game_paused).w move.b #1,($FFFFF003).w rts Next, find SpecialStage_Unpause, which should be this: Code (Text): ; loc_541A: SpecialStage_Unpause: move.b #MusID_Unpause,(Music_to_play).w move.b #8,(Vint_routine).w bra.w WaitForVint And replace it with this: Code (Text): ; loc_541A: SpecialStage_Unpause: move.b #1,($FFFFF003).w move.b #8,(Vint_routine).w bra.w WaitForVint Finally, we're going to do something that will clean up some RAM for us later in the guide. Do a search and replace (Usually CTRL+H) for "Underwater_palette_2". Replace all with "Underwater_palette". I don't know why the game used two different section for underwater palettes, but I've done this change in my hack and it did no harm. We're done with the first part of this guide! Try to build your Rom, and you'll get some errors! Fun! Next up, we'll be fixing these errors. Step 4 - Break it until it's fixed! --------------------------------------------------------------------------------------------------------------------------------------------------------------- If you look at the log, you'll see a lot of errors like this one: > > >Sonic 2 Clone Driver.asm(42): error: unknown opcode > > > INCBIN > > > PSG7: incbin sound\psg7.bin Luckily, this is a simple fix. Open up Sonic 2 Clone Driver.asm, anf find and replace (CRTL+H usually) all instances of "INCBIN" with "BINCLUDE" (Without the quotes, obviously). Now repeat the process, replacing all intances of "@loc" with "Lloc". The HG dissasembly does not like local routines, so this converts them into normal routines to avoid errors. Save the file, and compile the ROM again. I got 437 errors, and of course, they need to be fixed as well. On the bright side, you can close s2.asm and Sonic 2 Clone Driver.asn, they are all fixed. Step 5 - Strippers ------------------------------------------------------------------------------------------------------------------------------------------------------------------ Re-Open s2.sounddriver.asm, because we need to strip it down even more. Find zDACPtrTbl, and delete everything down to the line "idstart := 81h" Go to "zBankSwitchToMusic:", and delete the contents of that routine.(Everything between "zBankSwitchToMusic:" and "ret" Go to "zUpdateDAC:" and again delete everything down to "ret". Now find this line: Code (Text): ensure1byteoffset macro maxsize Delete everything between that and endm, but leave those two lines, otherwise you will get errors. If you build the ROM now, you will get 393 errors, but almost all of these are duplicates or fixed just by fixing another. Don't close s2.sounddriver.asm just yet, we'll be stripping more content from that later. Right now however, we're going to fix the bulk of these errors. Step 6 - Identity Crisis ------------------------------------------------------------------------------------------------------------------------------------------------------------------ Open s2.constants.asm. 393 is a lot of errors, but all it takes to fix them is a copy+paste job for you. Find the line "; Music IDs". You'll see this: Code (Text): ; Music IDs offset := zMasterPlaylist ptrsize := 1 idstart := $81 ; $80 is reserved for silence, so if you make idstart $80 or less, ; you may need to insert a dummy zMusIDPtr in the $80 slot delete everything from there down to "MusID__End = id(zMusIDPtr__End) ; A0", and paste the following where it used to be: Code (Text): ; Music IDs offset := MusicIndex ptrsize := 1 idstart := $81 ; $80 is reserved for silence, so if you make idstart $80 or less, ; you may need to insert a dummy zMusIDPtr in the $80 slot MusID__First = idstart MusID_2PResult = $81 MusID_EHZ = $82 MusID_MCZ_2P = $83 MusID_OOZ = $84 MusID_MTZ = $85 MusID_HTZ = $86 MusID_ARZ = $87 MusID_CNZ_2P = $88 MusID_CNZ = $89 MusID_DEZ = $8A MusID_MCZ = $8B MusID_EHZ_2P = $8C MusID_SCZ = $8D MusID_CPZ = $8E MusID_WFZ = $8F MusID_HPZ = $90 MusID_Options = $91 MusID_SpecStage = $92 MusID_Boss = $93 MusID_EndBoss = $94 MusID_Ending = $95 MusID_SuperSonic = $96 MusID_Invincible = $97 MusID_ExtraLife = $98 MusID_Title = $99 MusID_EndLevel = $9A MusID_GameOver = $9B MusID_Continue = $9C MusID_Emerald = $9D MusID_Credits = $9E MusID_Countdown = $9F MusID__End = $A0 The music is all fixed, now all that's left is the sound effects: Find the line "; Sound IDs", and delete everything down to the line "; Special sound IDs". Leve the special IDs alone. In place of the text you deleted, just paste this: Code (Text): ; Sound IDs offset := SoundIndex ptrsize := 2 idstart := $A0 SndID__First = idstart SndID_Jump = $A0 ; A0 SndID_Checkpoint = $A1 ; A1 SndID_SpikeSwitch = $A2 ; A2 SndID_Hurt = $A3 ; A3 SndID_Skidding = $A4 ; A4 SndID_BlockPush = $A5 ; A5 SndID_HurtBySpikes = $A6 ; A6 SndID_Sparkle = $A7 SndID_Beep = $A8 SndID_Bwoop = $A9 SndID_Splash = $AA SndID_Swish = $AB SndID_BossHit = $AC SndID_InhalingBubble = $AD SndID_ArrowFiring = $AE SndID_LavaBall = $AE SndID_Shield = $Af SndID_LaserBeam = $B0 SndID_Zap = $B1 SndID_Drown = $B2 SndID_FireBurn = $B3 SndID_Bumper = $B4 SndID_Ring = $B5 ; B5 SndID_RingRight = $B5 SndID_SpikesMove = $B6 SndID_Rumbling = $B7 SndID_Smash = $B9 SndID_DoorSlam = $BB SndID_SpindashRelease = $BC ; BC SndID_Hammer = $BD SndID_Roll = $BE SndID_ContinueJingle = $BF SndID_CasinoBonus = $C0 SndID_Explosion = $C1 SndID_WaterWarning = $C2 SndID_EnterGiantRing = $C3 SndID_BossExplosion = $C4 SndID_TallyEnd = $C5 SndID_RingSpill = $C6 SndID_Flamethrower = $C8 SndID_Bonus = $C9 SndID_SpecStageEntry = $CA SndID_SlowSmash = $CB SndID_Spring = $CC SndID_Blip = $CD SndID_RingLeft = $B5 SndID_Signpost = $CF SndID_CNZBossZap = $D0 SndID_Signpost2P = $D3 SndID_OOZLidPop = $D4 SndID_SlidingSpike = $D5 SndID_CNZElevator = $D6 SndID_PlatformKnock = $D7 SndID_BonusBumper = $D8 SndID_LargeBumper = $D9 SndID_Gloop = $DA SndID_PreArrowFiring = $DB SndID_Fire = $DC SndID_ArrowStick = $DD SndID_Helicopter = $DE SndID_SuperTransform = $DF SndID_SpindashRev = $E0 SndID_Rumbling2 = $E1 SndID_CNZLaunch = $E2 SndID_Flipper = $E3 SndID_HTZLiftClick = $E4 SndID_Leaves = $E5 SndID_MegaMackDrop = $E6 SndID_DrawbridgeMove = $E7 SndID_QuickDoorSlam = $E8 SndID_DrawbridgeDown = $E9 SndID_LaserBurst = $EA SndID_Scatter = $EB SndID_LaserFloor = $EB SndID_Teleport = $EC SndID_Error = $ED SndID_MechaSonicBuzz = $EE SndID_LargeLaser = $EF SndID_OilSlide = $F0 SndID__End = $F7 Step 7 - I am Error ------------------------------------------------------------------------------------------------------------------------------------------------------------------ Now we are going back to s2.sounddriver.asm. There are 4 more errors here. As before, we're going to solve this by simply emptying out the relavent routines. We can't just delete stuff because a few things in it are still going to be referenced. So the first Routine to clean out is zDACAfterDur. change that and remove zloc_22A inside it so it looks like this: Code (Text): zDACAfterDur: ret There is one more routine to empty. That routine is zloc_78E, or zBGMLoad. Starting at this line: Code (Text): zBGMLoad: delete everything down to here: Code (Text): ; End of DAC/FM init, begin PSG init And there you have it! Close s2.sounddriver.asm, Build you ROM and test it! Additional Step ------------------------------------------------------------------------------------------------------------------------------------------------------------------ Uh-oh! if you've played up to Chemical Plant Zone Act 2, you'll notice the driver crashes on that level! This is because of water. In Sonic 2, the underwater palettes are stored in a section of RAM that is now used by the sound driver, because it's based on Sonic 1's sound driver. What we need to do now is relocate the water palette table in RAM, so the Sound Driver can do what it likes. I am going to assume you haven't modified the RAM allocation in your hack here, and go step by step. If you have modifying the RAM in your game, you are probably on your own. Let's go back to s2.constants.asm, and find these lines: Code (Text): Underwater_palette_2: ds.w palette_line_size ; not sure what it's used for but it's only used when there's water Underwater_palette_2_line2: ds.w palette_line_size Underwater_palette_2_line3: ds.w palette_line_size Underwater_palette_2_line4: ds.w palette_line_size Underwater_palette: ds.w palette_line_size ; main palette for underwater parts of the screen Underwater_palette_line2: ds.w palette_line_size Underwater_palette_line3: ds.w palette_line_size Underwater_palette_line4: ds.w palette_line_size ds.b $500 ; $FFFFF100-$FFFFF5FF ; unused, leftover from the Sonic 1 sound driver (and used by it when you port it to Sonic 2) The last four lines before the ds.b $500 are used by the sound driver now, in addition to the 500 that is labeled as such. Replace all of the above lines with this: Code (Text): ds.b $100 ; Sonic 1 Sound Driver ds.b $500 ; Sonic 1 Sound Driver After doing that, you will need to find at least $80 free bytes in RAM (besides the space we just put in) Fortunately, there is an area of RAM that has $C0 free bytes, and that is where the four lines we lost will go. Search for this: Code (Text): CNZ_saucer_data: And you will see this: Code (Text): CNZ_saucer_data: ds.b $40 ; the number of saucer bumpers in a group which have been destroyed. Used to decide when to give 500 points instead of 10 ds.b $C0 ; $FFFFE740-$FFFFE7FF ; unused as far as I can tell Ring_Positions: ds.b $600 Replace it with this: Code (Text): CNZ_saucer_data: ds.b $40 ; the number of saucer bumpers in a group which have been destroyed. Used to decide when to give 500 points instead of 10 Underwater_palette: ds.w palette_line_size ; main palette for underwater parts of the screen Underwater_palette_line2: ds.w palette_line_size Underwater_palette_line3: ds.w palette_line_size Underwater_palette_line4: ds.w palette_line_size ds.b $40 ; $FFFFE740-$FFFFE7FF ; unused as far as I can tell Ring_Positions: ds.b $600 Build it, and test! The sega sound will be glitched up, and you can fix it by following this link. Everything that needs to be fixed will be in "Sonic 2 Clone Driver.asm". ------------------------------------------------------------------------------------------------------------------------------------------------------------------ Credits Varion Icaria - Puto's sound driver port. Esrael - Tweakers driver port, plus fixes for things broken in Puto's port, such as hanging on the title card. Extra thanks for fixing the Sega sound. Puto - Fixes for underwater palette stuff, as well as special stage ring stuff, and various other fixes. StephenUK - Hints on how to fix the underwater stuff. drx - Hacking CulT's VDP calculator. Tweaker - Wrote the orignal guide to port Sonic 1's sound driver into Sonic 2. ValleyBell - lots of miscallanious help to get this to work, as well as worked on the Sonic 2 Clone Driver. ShadowsofYesterday - Telling me the fix for the SEGA sound. Caverns4 - I wrote this guide! I'm posting this here because I wanted to get some input on improvements I can make, or changes I need to make before posting a How-To on the Wiki. If anyone has any suggestions or help, I would appreciate it very much. One other thing I wasnt cleared up is the credits - did I miss anyone?
Nice guide. Certain parts could use a bit more clarity, like the ds.b $100 thing near the end there (how many of those lines am I replacing with that? All of them, or just four?), but overall it makes something that's a pain in the neck much easier to do, and to my knowledge there isn't an existing guide of this out there. Liked, commented, and subscribed. Also, the "of" in my name isn't capitalized, but it's a common mistake.
Alright, since it's been here a while with no response, I'm working off the assumption that everything is fine, and and I have posted the guide on the Wiki here: http://info.sonicretro.org/Port_the_Sonic_2_Clone_Sound_Driver_to_the_HG_version_of_Sonic_2 I forgot the "SCHG How-To:" prefix, so I don't know if anyone is capable of editing page titles, but I would appreciate it. I thought is was added automatically to How-to's. Again though, if there are any other issues with this guide, feel free to let me know.
Thank you very much! There is one more thing I noticed. under the table for SCHG How-To Guide: Sonic the Hedgehog 2 (16-bit) atthe bottom of the page, my guide doesn't appear on there. It should be there under "Extending the Game". What's wrong?
Thanks for the guide, Caverns 4, I have been using it myself until recently, and I believe I have some useful information: while examining the original Sonic 1 sound driver guide for the Xenowhirl disassembly, I noticed that towards the end, the author mentioned removing the Sonic 2 sound driver, and I began thinking "Can the Clone Driver completely replace the original?" which pretty much translates to "Is there a way to just delete s2.sounddriver.asm without incurring several thousand errors?", unfortunately, the guide didn't specify how, leaving it to our imaginations. Now I can happily say that I have found a way, this eliminates the stripping detailed in your guide but doesn't fix any of the faults you mentioned, such as the rev-less spindash or another fault I had discovered: the music doesn't speed up correctly. I have, however, a fix for one two and *a* finding for the other. First though, is my method of porting the Clone Driver, the main benefit, as I mentioned, is the elimination of s2.soundriver.asm. Spoiler —SETTING UP— Spoiler As before, delete the contents of the sound folder and extract Sonic 2 Clone Driver.asm along with the new sound folder into your disassembly's main directory. Open s2.asm, s2.constants.asm, and Sonic 2 Clone Driver.asm in a suitable text editor. Switch to Sonic 2 Clone Driver.asm —CLEANING UP THE CLONE DRIVER— Spoiler Now, I don't quite understand when or why this happened, but at the beginning of the Clone Driver's code, you can find a copy of a Sonic 1 sound driver compatible version of SoundDriverLoad, this causes that error Caverns 4 described when he said to delete the one in s2.asm. The copy found in Sonic 2 Clone Driver.asm didn't exist in the original release of the Clone Driver (the one with the faulty EC sound). Anyway, this version of SoundDriverLoad appears to work just fine if you use it instead of the one I'll bring up later, so make your choice, if you don't wish to use it, delete it, it's just wasted space otherwise. Now we need to remove some unneeded and potentially catastrophic code; depending on where you include the Clone Driver, this could create a colossal amount of symbol undefined errors among others. Scroll to the bottom of the Clone Driver's code and look for this: Code (ASM): EndofRom: END Delete it. Explanation Spoiler This is already defined in s2.asm, and unlike this one, it's actually at the appropriate location; at the end of the ROM. You can guess why this can cause such damage if left intact. Caverns 4's guide masked this by including the Clone Driver just before s2.asm's EndofRom. Finally, replace all instances of "incbin" with "BINCLUDE" and "@loc" with "Lloc". Explanation Spoiler The Clone Driver's code was adapted for another compiler, making it incompatible with the AS compiler, which the HG disassembly uses, this fix simply makes it compatible. That's it for now. Switch to s2.asm —REPLACING THE Z80 DRIVER— Spoiler Go to Snd_Driver and you'll see this: Code (ASM): Snd_Driver: include "s2.sounddriver.asm" ; CPU Z80 CPU 68000 padding off listing off supmode on !org (Snd_Driver+Size_of_Snd_driver_guess) ; don't worry; I know what I'm doing ; loc_ED04C: Snd_Driver_End: Replace it with this: Code (ASM): Snd_Driver: include "Sonic 2 Clone Driver.asm" ; loc_ED04C: Snd_Driver_End: Explanation Spoiler We're replacing the reference to the Sonic 2 Z80 driver with one to the modified Sonic 1 68k driver, eliminating the former entirely, no stripping, no wasted space, none of the code within s2.sounddriver.asm will be compiled with the ROM. This will create errors, but those will be fixed. The lines beneath the include won't be needed any more as they're only needed if s2.sounddriver.asm is included, which it isn't. The following is quoted from Caverns 4's guide, with some modifications to make use of the HG's RAM labels. Back to originality, find sndDriverInput and look for these lines: Code (ASM): lea (Z80_RAM+zComRange).l,a1 ; $A01B80 cmpi.b #$80,8(a1) ; If this (zReadyFlag) isn't $80, the driver is processing a previous sound request. bne.s loc_10C4 ; So we'll wait until at least the next frame before putting anything in there. Delete or comment them out. Explanation Spoiler The code calls for zComRange, which doesn't exist any more. I have found no negative effects of removing this code. Search and replace "Underwater_palette_2" with "Underwater_palette". —THE REAL STRIPPERS— Spoiler Search for "SndDAC_Start:" and above it you'll see this: Code (ASM): cnop -Size_of_DAC_samples, $8000 Delete it and everything from SndDAC_Start up to (and including) Mus_Continue. Explanation Spoiler They're unneeded by this point, and will only take up space. Taking some cues from Caverns 4's guide again, find the routine Snd_Sega and above it you'll find this: Code (ASM): cnop -Size_of_SEGA_sound, $8000 Delete it and everything from there up to (but not including) "; end of 'ROM'". Cavern 4's idea of emptying the Snd_Sega routine won't be needed here. SoundIndex and sounds Sound20 - Sound70 are among the code deleted, which is good as it saves us having to find and delete them separately. Explanation Spoiler Again, unused, unneeded, and just wastes space. Also, this code: Code (ASM): if * > soundBankStart + $8000 fatal "soundBank must fit in $8000 bytes but was $\{*-soundBankStart}. Try moving something to the other bank." else ;message "soundBank has $\{$8000+soundBankStart-*} bytes free at end." endif is also only needed if you kept the sounds, which we didn't, so it's been deleted too. Find SoundDriverLoad and delete the entire routine, you might as well since it's gonna become unused anyway. Now delete everything from DecompressSoundDriver to (and including) sub_EC0DE. Explanation Spoiler The Kosinski compressed sound driver isn't here any more, so this is useless, this causes an error which can be fixed by doing so: Find Code (ASM): shared word_728C_user,Obj5F_MapUnc_7240,off_3A294,MapRUnc_Sonic,movewZ80CompSize And just delete the last entry so you have this: Code (ASM): shared word_728C_user,Obj5F_MapUnc_7240,off_3A294,MapRUnc_Sonic I know there's a warning about deleting entries, but we needn't worry. That's it for s2.asm. Switch to s2.constants.asm. —CONSTANT QUOTING— Spoiler For the most part I'll be quoting Caverns 4 again with some table tweaks. In order to make the RAM labels we pointed to earlier work, we need to define them! Head back to the $600 bytes of free RAM and add a "Clone_Driver_RAM:" label before it, giving you this: Code (ASM): Clone_Driver_RAM: ds.b $600 ; leftover from the Sonic 1 sound driver (and used by it when you port it to Sonic 2) Now, save all and build, there should be no errors and have the Clone Driver working fully! I do not yet know if this works on real hardware, if anyone does, please do tell, I can confirm that this works on Fusion and MD.emu. Don't forget to apply the Sega sound fix and the fixes found below (if available). Here's the spindash rev fix. Spoiler I have ported the code from here to be compatible with the new layout and compiler (credit to shobiz for original code): All of this code is in Sonic 2 Clone Driver.asm. First, find loc_71BC8, it should look like this: Code (ASM): loc_71BC8: lea $40(a6),a5 tst.b (a5) bpl.s loc_71BD4 jsr sub_71C4E(pc) Replace it with this: Code (ASM): loc_71BC8: tst.b (Spindash_Timer).w beq.s + subq.b #1,(Spindash_Timer).w + lea $40(a6),a5 tst.b (a5) ; Is DAC track playing? bpl.s loc_71BD4 ; Branch if not jsr sub_71C4E(pc) Now find Sound_E0plus, it should look like this: Code (ASM): Sound_E0plus: cmpi.b #$F8,d7 bge.s Sound_ChkValue_OtherChecks subi.b #$E0,d7 bra.s Sound_ChkValue_OtherChecks Replace it with this: Code (ASM): Sound_E0plus: clr.b (Spindash_LastSound_Flag).w cmp.b #$E0,d7 ; is this the Spin Dash sound? bne.w +++ ; if not, branch move.w d0,-(sp) move.b (Spindash_Pitch).w,d0 ; store extra frequency tst.b (Spindash_Timer).w ; is the Spin Dash timer active? bne.s + ; if it is, branch move.b #-1,d0 ; otherwise, reset frequency (becomes 0 on next line) + addq.b #1,d0 cmp.b #$C,d0 ; has the limit been reached? bcc.s + ; if it has, branch move.b d0,(Spindash_Pitch).w ; otherwise, set new frequency + move.b #1,(Spindash_LastSound_Flag).w ; set flag move.b #60,(Spindash_Timer).w ; set timer move.w (sp)+,d0 + cmpi.b #$F8,d7 bge.s Sound_ChkValue_OtherChecks subi.b #$E0,d7 bra.s Sound_ChkValue_OtherChecks Find Sound_A0toCF and look for this: Code (ASM): tst.b $24(a6) bne.w loc_722C6 After it, add Code (ASM): clr.b (Spindash_LastSound_Flag).w Go to loc_7226E and replace Code (ASM): movea.l dword_722EC(pc,d3.w),a5 with Code (ASM): lea dword_722EC(pc),a5 movea.l (a5,d3.w),a5 Now find loc_72276 and replace Code (ASM): move.w (a1)+,8(a5) move.b #1,$E(a5) with Code (ASM): move.w (a1)+,8(a5) tst.b (Spindash_LastSound_Flag).w ; is the Spin Dash sound playing? beq.s + ; if not, branch move.w d0,-(sp) move.b (Spindash_Pitch).w,d0 add.b d0,8(a5) move.w (sp)+,d0 + move.b #1,$E(a5) Now we need to declare some RAM variables, this shouldn't be too hard given that we're using the HG disassembly: Open s2.constants.asm and look for three of these (they don't have to be together): Code (ASM): ds.b 1 ; $FFFFXXXX ; seems unused And tack "Spindash_LastSound_Flag" before one of them, "Spindash_Pitch" before another, and "Spindash_Timer" before the last one, so you have these replacing them: Code (ASM): Spindash_LastSound_Flag: ds.b 1 ; $FFFFXXXX ; seems unused Spindash_Pitch: ds.b 1 ; $FFFFXXXX ; seems unused Spindash_Timer: ds.b 1 ; $FFFFXXXX ; seems unused I'd recommend that you only use byte length values, for the sake of being efficient (after all, there is around 3C0 (excluding that leftover from the Sonic 1 sound driver) bytes of completely unused RAM floating about, most of which is in single separate bytes). For those that don't understand what I'm talking about, just find this: Code (ASM): ds.b 3 ; $FFFFEEE9-$FFFFEEEB ; seems unused And replace it with this: Code (ASM): Spindash_LastSound_Flag: ds.b 1 Spindash_Pitch: ds.b 1 Spindash_Timer: ds.b 1 That should do it. Fixing the PSGs. Spoiler As Caverns 4 mentioned, certain PSG channels sound wrong, such as EHZ's. The reason? They use the wrong PSGs. PSG instruments? PSG voices? I'm not sure. For now I'll just call them "PSGs". I don't know why, but instead of extracting the 4 new PSGs from Sonic 2 and adding them to the Clone Driver, the makers simply changed all references to these PSGs to point to other available PSGs, and even then they missed a few. To my knowledge, the songs affected by this are 82 (EHZ), 83 (MCZ 2 player VS), 84 (OOZ), 8B (MCZ), 8C (EHZ 2 player VS), 92 (Special stage), 95 (Ending), and 9E (Credits). Give them a listen and compare them. So, fixing this will require that we find and add these new PSGs from s2.sounddriver.asm to Sonic 2 Clone Driver.asm, then use modified music file that use them. Open up s2.sounddriver.asm and head to zPSG_FlutterTbl, unlike the Clone Driver, the PSGs aren't BINCLUDEd or included, instead being a part of the main file. The first nine entries are the oh so familiar Sonic 1 PSGs, unmodified too. The next four are new, so we need to port (read: copy and paste) those. We're going to do this in a similar fashion to the ones already included in the Clone Driver; BINCLUDEd .bin files. To begin, just type them up into a hex editor, adding zeros before each single-digit value. For example, PSG 10 should look like this: Spoiler 00 00 00 00 00 00 00 00 00 00 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 02 02 02 02 02 02 02 02 02 02 03 03 03 03 03 03 03 03 03 03 04 80 Then save each PSG to their own file, naming them "psg10.bin" through "psg13.bin" and placing them in the sound folder. Now, at the top of Sonic 2 Clone Driver.asm, you should be able to find this: Code (ASM): ; --------------------------------------------------------------------------- ; PSG instruments used in music ; --------------------------------------------------------------------------- PSG_Index: dc.l PSG1, PSG2, PSG3 dc.l PSG4, PSG5, PSG6 dc.l PSG7, PSG8, PSG9 PSG1: BINCLUDE sound\psg\psg1.bin PSG2: BINCLUDE sound\psg\psg2.bin PSG3: BINCLUDE sound\psg\psg3.bin PSG4: BINCLUDE sound\psg\psg4.bin PSG6: BINCLUDE sound\psg\psg6.bin PSG5: BINCLUDE sound\psg\psg5.bin PSG7: BINCLUDE sound\psg\psg7.bin PSG8: BINCLUDE sound\psg\psg8.bin PSG9: BINCLUDE sound\psg\psg9.bin Here we shall define our new PSGs. Add some BINCLUDEs pointing to the .bins and point the index to them. You should be left with this: Code (ASM): ; --------------------------------------------------------------------------- ; PSG instruments used in music ; --------------------------------------------------------------------------- PSG_Index: dc.l PSG1, PSG2, PSG3 dc.l PSG4, PSG5, PSG6 dc.l PSG7, PSG8, PSG9 dc.l PSG10,PSG11,PSG12 dc.l PSG13 PSG1: BINCLUDE sound\psg\psg1.bin PSG2: BINCLUDE sound\psg\psg2.bin PSG3: BINCLUDE sound\psg\psg3.bin PSG4: BINCLUDE sound\psg\psg4.bin PSG6: BINCLUDE sound\psg\psg6.bin PSG5: BINCLUDE sound\psg\psg5.bin PSG7: BINCLUDE sound\psg\psg7.bin PSG8: BINCLUDE sound\psg\psg8.bin PSG9: BINCLUDE sound\psg\psg9.bin PSG10: BINCLUDE sound\psg\psg10.bin PSG11: BINCLUDE sound\psg\psg11.bin PSG12: BINCLUDE sound\psg\psg12.bin PSG13: BINCLUDE sound\psg\psg13.bin That's the PSGs added, now to get the songs that use them, here are the already hacktastic music files hacked further to use the PSGs, link here. Sorry for the not being able to go into much depth with this part. I just reverse engineered an asm version of each song with the fixes added and applied the changes to the hex equivalents. Put these into your sound folder and overwrite if needed. Here's what (little) I have on the music speed up. Spoiler The music speed up isn't as simple as I hoped it would be, I haven't gotten very far into this due to lack of interest (for now). Open up s2.sounddriver.asm and look for zSpedUpTempoTable, it's what you think it is. An equivalent table exists in the Clone Driver, but isn't changed from Sonic 1, it is labelled byte_71A94. The Sonic 1 sound driver is better annotated and documented in the Sonic 1 HG disassembly than it is in the Clone Driver, so I'd look there for further references. I applied the values found in zSpedUpTempoTable to byte_71A94 and had little results; the speed simply wasn't right, Emerald Hill Zone is definitely off, Casino Night sounded off too, both were WAY too slow, if anything, I don't think they changed at all. I haven't looked any further than that, sorry.
This reminds me, while helping someone to port the Clone Driver to Sonic 2 HG, I tried making a clean-as-possible port by myself. (I just forgot to post it.) The results were these notes: (copy-pasted from my .txt file) Spoiler Code (Text): 1. remove sound directory remove s2.sounddriver.asm 2. open s2.asm remove everything from ; Subroutine to load the sound driver to Mus_Continue: BINCLUDE "sound/music/Continue.bin" This removes the routines SoundDriverLoad and DecompressSoundDriver. Then remove everything from cnop -Size_of_SEGA_sound, $8000 to the line above of ; end of 'ROM' Also remove movewZ80CompSize from the list of shared symbols (at the bottom of s2.asm). Then remove the whole function sndDriverInput and all calls to it. Finally comment this line out: jmp (SoundDriverLoad).l to magically remove some of the "addressing mode not allowed" errors. 3. open s2.constants.asm Remove everthing from ; Music IDs to SndID__End = ... and replace them with Caverns 4's MusID and SndID lines. Be sure to get rid of any "offset :=", "ptrsize :=", "idstart :=" and "... = idstart" lines. 4. Complile and test. You should now have a fully working (aside from the lack of sound) Sonic 2 ROM. 5. open s2.constants.asm Then search for Underwater_palette_2 and cut those 8 lines that start with Underwater_. Now change line below, which is ds.b $500 to ds.b $600 Now search for Normal_palette and paste the cut lines above of it. The line above of the block you pasted should be ds.b $80 ; unused, but SAT buffer can spill over into this area when there are too many sprites on-screen Remove it. and change the line directly above to Sprite_Table: ds.b $200 5. Unpack the Clone Driver and its files and folders into the root directory of the disassembly. 6. In s2.asm, right above of ; end of 'ROM' put include "Sonic 2 Clone Driver.asm" 7. Reactivate the line jmp (SoundDriverLoad).l 8. Open Sonic 2 Clone Driver.asm and replace all "incbin" with "binclude". Then fix the @ labels by replacing "@loc" with "Lloc". Finally, comment these 2 lines out: EndofRom: END [It should compile after this step.] 9. Open s2.asm Right after VintRet: insert jsr Init_Sonic1_Sound_Driver [Note: The correct name for this routine would be "Update_Sonic1_Sound_Driver", since it updates the sound driver and doesn't initialize it. Feel free to fix that.] 10. Replace the PlayMusic routine with this: PlayMusic: move.b d0,($FFFFF00A).w rts 11. Replace SFX_to_play and SFX_to_play_2 with $FFFFF00B. 12. Replace move.b #MusID_Pause,(Music_to_play).w ; pause music with move.b #1,($FFFFF003).w ; pause music and replace move.b #MusID_Unpause,(Music_to_play).w with move.b #$80,($FFFFF003).w ; resume music 13. Compile, test and enjoy a ROM of Sonic 2 with the Clone Driver. 14. Oh, wait. Ouch - that SEGA sound is corrupted and sounds horrible. Let's fix that quickly. Open Sonic 2 Clone Driver.asm and search for "SegaPCM:". Now, replace cnop $0, (((((*+$6978)>>$10)+$01)*$10000)-$6978) SegaPCM: binclude sound\segapcm.bin even with align $8000 SegaPCM: binclude sound\segapcm.bin SegaPCM_End: Yeah, most of them are cosmetic changes, but let's continue. Search for "PCM_Table:" and append this to the end of the table: dc.l $A00200, SegaPCM dc.w (SegaPCM_End-SegaPCM)/2 dc.b $09, 0 Finally, go to "Sound_E1:" and replace move.b #$88,($A01FFF).l with move.b #$88, d0 jsr Calculate_PCM move.b #$81, ($A01FFF).l ; can't use #$88, because that one uses hardcoded offsets Done. Yes, it can be that easy. Note: The word "replace" means "replace all occurrences of it". It should strip everything related to the S2 sound driver. (unless I missed something) And although it doesn't include the spindash fix, it includes a quick and easy fix for the SEGA sound issue. About the speed up table: The tempo algorithms between Sonic 1 and Sonic 2 are completely different, so you'll need to translate the tempo values. There are formulas to convert tempo value between any of the Sonic games on the wiki: SCHG:Music_Hacking/Pointer_and_Header_Format#SMPS_main_header btw: The SoundDriverLoad was probably added by me. But because I'm cleaning Sonic 2 of all sound code first and insert the Clone Driver then, this wasn't a problem for me. This has also the advantage, that it's easily possible to insert the Clone Driver into any other game. (You'd possibly need to port the KosDec, too.)