Sonic 2 (Simon Wai Prototype) Level Select in Sonic 1

you probably wonder why sonic2 beta has that level select that looks almost like the sonic1 level select and how sonic2 nick arcade prototype has one that is the sonic1 level select, well, that is what we are going to make the one in sonic1 behave like.

First, lets look at an overview of what our level select code looks like in a normal sonic1 (It is from the Hivebrain disassembly): <asm>

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Level Select

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LevelSelect: move.b #4,($FFFFF62A).w bsr.w DelayProgram bsr.w LevSelControls bsr.w RunPLC_RAM tst.l ($FFFFF680).w bne.s LevelSelect andi.b #$F0,($FFFFF605).w ; is A, B, C, or Start pressed? beq.s LevelSelect ; if not, branch move.w ($FFFFFF82).w,d0 cmpi.w #$14,d0 ; have you selected item $14 (sound test)? bne.s LevSel_Level_SS ; if not, go to Level/SS subroutine move.w ($FFFFFF84).w,d0 addi.w #$80,d0 tst.b ($FFFFFFE3).w ; is Japanese Credits cheat on? beq.s LevSel_NoCheat ; if not, branch cmpi.w #$9F,d0 ; is sound $9F being played? beq.s LevSel_Ending ; if yes, branch cmpi.w #$9E,d0 ; is sound $9E being played? beq.s LevSel_Credits ; if yes, branch

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

LevSel_PlaySnd: bsr.w PlaySound_Special bra.s LevelSelect

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LevSel_Ending: ; XREF: LevelSelect move.b #$18,($FFFFF600).w ; set screen mode to $18 (Ending) move.w #$600,($FFFFFE10).w ; set level to 0600 (Ending) rts

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LevSel_Credits: ; XREF: LevelSelect move.b #$1C,($FFFFF600).w ; set screen mode to $1C (Credits) move.b #$91,d0 bsr.w PlaySound_Special ; play credits music move.w #0,($FFFFFFF4).w rts

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LevSel_Level_SS: ; XREF: LevelSelect add.w d0,d0 move.w LSelectPointers(pc,d0.w),d0 ; load level number bmi.w LevelSelect cmpi.w #$700,d0 ; check if level is 0700 (Special Stage) bne.s LevSel_Level ; if not, branch move.b #$10,($FFFFF600).w ; set screen mode to $10 (Special Stage) clr.w ($FFFFFE10).w ; clear level move.b #3,($FFFFFE12).w ; set lives to 3 moveq #0,d0 move.w d0,($FFFFFE20).w ; clear rings move.l d0,($FFFFFE22).w ; clear time move.l d0,($FFFFFE26).w ; clear score rts

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LevSel_Level: ; XREF: LevSel_Level_SS andi.w #$3FFF,d0 move.w d0,($FFFFFE10).w ; set level number

PlayLevel: ; XREF: ROM:00003246�j ... move.b #$C,($FFFFF600).w ; set screen mode to $0C (level) move.b #3,($FFFFFE12).w ; set lives to 3 moveq #0,d0 move.w d0,($FFFFFE20).w ; clear rings move.l d0,($FFFFFE22).w ; clear time move.l d0,($FFFFFE26).w ; clear score move.b d0,($FFFFFE16).w ; clear special stage number move.b d0,($FFFFFE57).w ; clear emeralds move.l d0,($FFFFFE58).w ; clear emeralds move.l d0,($FFFFFE5C).w ; clear emeralds move.b d0,($FFFFFE18).w ; clear continues move.b #$E0,d0 bsr.w PlaySound_Special ; fade out music rts

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Level select - level pointers

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LSelectPointers: binclude misc\ls_point.bin align 2

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Level select codes

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LevelSelectCode_J: binclude misc\ls_jcode.bin align 2

LevelSelectCode_US: binclude misc\ls_ucode.bin align 2

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</asm>