P128 Rev01 Guide Restored

MARKEYJESTER'S GUIDE ON PORTING REV01 EFFECTS TO PROJECT SONIC 1: TWO-EIGHT
RESTORED BY KILO SINCE SONIC RETRO'S FORMATTING UPDATES DESTROYED IT. AND PEOPLE SHOULDN'T HAVE TO USE A SHITTY GIT FORK.

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goto sub_6886:
change

        lea ($FFFFA440).w,a4

to

        movea.l ($FFFFA404).w,a4    ; MJ: Load address of layout BG

----------------------------------------------------

goto LoadTilesAsYouMove:
change

        lea ($FFFFA440).w,a4

to

        movea.l ($FFFFA404).w,a4    ; MJ: Load address of layout BG

and change

        lea ($FFFFA400).w,a4

to

        movea.l ($FFFFA400).w,a4    ; MJ: Load address of layout

----------------------------------------------------

goto sub_70AC:  (Was sub_6B32: in normal S1)
change

        btst    #4,(a0)

to

        btst    #3,(a0) ; MJ: checking bit 3 not 4 (Flip)

and change

        btst    #3,(a0)

to

        btst    #2,(a0) ; MJ: checking bit 2 not 3 (Mirror)

----------------------------------------------------

goto loc_70E8: (Was loc_6B6E: in normal S1)
change

        btst    #3,(a0)

to

        btst    #2,(a0) ; MJ: checking bit 2 not 3 (Mirror)

----------------------------------------------------

goto loc_712C: (Was sub_6BD6: in normal S1)
remove

        lsr.w   #1,d3

change

        andi.w  #$380,d3

to

        andi.w  #$780,d3    ; MJ: get within 780 (Not 380) (E00 pixels (not 700)) in multiples of 80

and change

        lsr.w   #5,d0

to

        lsr.w   #4,d0   ; MJ: divide by 10 (Not 20)

under this command

        andi.w  #$7F,d0

insert this

        lsl.w   #$01,d3 ; MJ: multiply by 2 (So it skips the BG)

remove these two

        beq.s   locret_7172
        subq.b  #1,d3

change

        andi.w  #$7F,d3

to

        andi.w  #$FF,d3 ; MJ: keep within FF

under this command

        ror.w   #7,d3

insert this

        ror.w   #2,d3   ; MJ: ..plus an extra 2 (so it's within 80 bytes, not 200)

remove

        add.w   d4,d4

change these two

        andi.w  #$1E0,d4
        andi.w  #$1E,d5

to this

        andi.w      #$070,d4    ; MJ: keep Y pos within 80 pixels
        andi.w      #$0E,d5 ; MJ: keep X pos within 10

----------------------------------------------------

goto LoadTilesFromStart:
change

        lea ($FFFFA400).w,a4

to

        movea.l ($FFFFA400).w,a4    ; MJ: Load address of layout

and change

        lea ($FFFFA440).w,a4

to

        movea.l ($FFFFA404).w,a4    ; MJ: Load address of layout BG

----------------------------------------------------