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SCHG How-to

Expand the music index from $94 to $9F

From Sonic Retro

Revision as of 13:59, 13 November 2009 by SOTI (talk | contribs) (Created page with '{{GuideBy|lukeusher123}} To add more music slots to the sound test, search for this code in the level select routine: <asm>LevSel_NoCheat: cmpi.w #$94,d0 ; is soun…')
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(Original guide by lukeusher123)

To add more music slots to the sound test, search for this code in the level select routine: <asm>LevSel_NoCheat:

       cmpi.w    #$94,d0    ; is sound $80-$94 being played?
       bcs.s    LevSel_PlaySnd; if yes, branch
       cmpi.w    #$A0,d0    ; is sound $95-$A0 being played?
       bcs.s    LevelSelect; if yes, branch</asm>

Change the line: <asm> cmpi.w #$94,d0  ; is sound $80-$94 being played?</asm> So it reads: <asm> cmpi.w #$9F,d0  ; is sound $80-$94 being played?</asm> Then rebuild the rom.

And now the sound test will have the music slots going up to $9F, instead of $94, however attempts to play empty music slots will crash the sound driver, and possibly lock up the emulator. So, make sure you include a song in every slot.