Mini-tutorials Thread

v_player = $FFFFD000

 

HOW TO GET A SONIC 3 ESQUE TITLE CARD BANNER IN SONIC 1 HIVEBRAIN

*Quick note :This is simple to put into Github's disassembly aswell (Update coming Soon).

So first you need to find "Map_obj34", It should look like this

Code:

Map_obj34:    dc.w byte_C9FE-Map_obj34
        dc.w byte_CA2C-Map_obj34
        dc.w byte_CA5A-Map_obj34
        dc.w byte_CA7A-Map_obj34
        dc.w byte_CAA8-Map_obj34
        dc.w byte_CADC-Map_obj34
        dc.w byte_CB10-Map_obj34
        dc.w byte_CB26-Map_obj34
        dc.w byte_CB31-Map_obj34
        dc.w byte_CB3C-Map_obj34
        dc.w byte_CB47-Map_obj34  ; byte_CB47 is the Oval
        dc.w byte_CB8A-Map_obj34

And obviously marked byte_CB47, is the Oval. So just paste this code into "byte_CB47"

Code:

byte_CB47:    dc.b $30
        dc.b $A0, 5, 0, $7C, $F8
        dc.b $A0, 5, 0, $7C, 8
        dc.b $B0, 5, 0, $7C, $F8
        dc.b $B0, 5, 0, $7C, 8
        dc.b $A0, 5, 0, $7C, $18
        dc.b $B0, 5, 0, $7C, $18
        dc.b $C0, 5, 0, $7C, $F8
        dc.b $C0, 5, 0, $7C, 8
        dc.b $C0, 5, 0, $7C, $18
        dc.b $D0, 5, 0, $7C, $F8
        dc.b $E0, 5, 0, $7C, $F8
        dc.b $F0, 5, 0, $7C, $F8
        dc.b 0, 5, 0, $7C, $F8
        dc.b $10, 5, 0, $7C, $F8
        dc.b $10, 5, 0, $7C, 8
        dc.b $10, 5, 0, $7C, $18
        dc.b 0, 5, 0, $7C, 8
        dc.b 0, 5, 0, $7C, $18
        dc.b $F0, 5, 0, $7C, 8
        dc.b $F0, 5, 0, $7C, $18
        dc.b $D0, 5, 0, $7C, 8
        dc.b $D0, 5, 0, $7C, $18
        dc.b $E0, 5, 0, $7C, 8
        dc.b $E0, 5, 0, $7C, $18
        dc.b $20, 5, 0, $7C, $F8
        dc.b $30, 5, 0, $7C, $F8
        dc.b $20, 5, 0, $7C, 8
        dc.b $30, 5, 0, $7C, 8
        dc.b $20, 5, 0, $7C, $18
        dc.b $30, 5, 0, $7C, $18
        dc.b $30, 5, 0, $7C, $E8
        dc.b $20, 5, 0, $7C, $E8
        dc.b $10, 5, 0, $7C, $E8
        dc.b 0, 5, 0, $7C, $E8
        dc.b $F0, 5, 0, $7C, $E8
        dc.b $E0, 5, 0, $7C, $E8
        dc.b $D0, 5, 0, $7C, $E8
        dc.b $C0, 5, 0, $7C, $E8
        dc.b $B0, 5, 0, $7C, $E8
        dc.b $A0, 5, 0, $7C, $E8
        dc.b $40, 5, 0, $7C, $E8
        dc.b $40, 5, 0, $7C, $F8
        dc.b $40, 5, 0, $7C, 8
        dc.b $40, 5, 0, $7C, $18
        dc.b $50, 5, 0, $7C, $E8
        dc.b $50, 5, 0, $7C, $F8
        dc.b $50, 5, 0, $7C, 8
        dc.b $50, 5, 0, $7C, $18

And you should result in in having a Sonic 3 Esque Title Card Banner, like this

*Edit 12:14 AM 3/30/2025: The Banner will only change color if Sonic's palette is altered (Cuz The blue is his blue).

 

Sorry to break the news to you, but the s3 title card banner is on the left and the color of it is red, although the different color could be a cool idea to show off different characters.

 

2 Questions:
1. Why Sonic disappears when the title card appears?

2. Uhhh... What?

 

That banner uses an absurd number of small little sprite pieces (48!!). The maximum number of sprites that can be displayed in one state is 80 sprites (when the horizontal resolution is 320px, 64 for 256px mode). That leaves very little space in the sprite table in VRAM for the other sprites, and as such, once space runs out, whatever sprites that won't fit just will not be displayed. It would be better to expand the blue tiles from 4 to 16 tiles, and use 32x32 sprite pieces instead of 16x16. It would cut the number of pieces down to just 12.

 

I know its not fully accurate to Sonic 3 but thats the banner Some hacks use, this can be fixed by just changing the X-Position.

 

(Original guide by Tweaker And Puto in Sonic Retro)
If you played Sonic 1, maybe you remember thhe speed cap, if not, heres a example.

Spoiler: Example

Already saying this, lets go to action!
Go to "_IncObj/Sonic Move.asm" And go to Sonic_MoveLeft, you will find this:

Code:

[/SIZE]
; ||||||||||||||| S U B    R O U T    I N E |||||||||||||||||||||||||||||||||||||||
Sonic_MoveLeft:
       move.w    obInertia(a0),d0
       beq.s    loc_13086
       bpl.s    loc_130B2
loc_13086:
       bset    #0,obStatus(a0)
       bne.s    loc_1309A
       bclr    #5,obStatus(a0)
       move.b    #id_Run,obPrevAni(a0) ; restart Sonic's animation
loc_1309A:
       sub.w    d5,d0
       move.w    d6,d1
       neg.w    d1
       cmp.w    d1,d0
       bgt.s    loc_130A6
       move.w    d1,d0
loc_130A6:
       move.w    d0,obInertia(a0)
       move.b    #id_Walk,obAnim(a0) ; use walking animation
       rts 
; ===========================================================================
loc_130B2:
       sub.w    d4,d0
       bcc.s    loc_130BA
       move.w    #-$80,d0
loc_130BA:
       move.w    d0,obInertia(a0)
       move.b    obAngle(a0),d0
       addi.b    #$20,d0
       andi.b    #$C0,d0
       bne.s    locret_130E8
       cmpi.w    #$400,d0
       blt.s    locret_130E8
       move.b    #id_Stop,obAnim(a0) ; use "stopping" animation
       bclr    #0,obStatus(a0)
       move.w    #sfx_Skid,d0
       jsr    (PlaySound_Special).l    ; play stopping sound
locret_130E8:
       rts 
; End of function Sonic_MoveLeft
; ||||||||||||||| S U B    R O U T    I N E |||||||||||||||||||||||||||||||||||||||
Sonic_MoveRight:
       move.w    obInertia(a0),d0
       bmi.s    loc_13118
       bclr    #0,obStatus(a0)
       beq.s    loc_13104
       bclr    #5,obStatus(a0)
       move.b    #id_Run,obPrevAni(a0) ; restart Sonic's animation
loc_13104:
       add.w    d5,d0
       cmp.w    d6,d0
       blt.s    loc_1310C
       move.w    d6,d0
loc_1310C:
       move.w    d0,obInertia(a0)
       move.b    #id_Walk,obAni
m(a0) ; use walking animation
       rts 
; ===========================================================================
loc_13118:
       add.w    d4,d0
       bcc.s    loc_13120
       move.w    #$80,d0
loc_13120:
       move.w    d0,obInertia(a0)
       move.b    obAngle(a0),d0
       addi.b    #$20,d0
       andi.b    #$C0,d0
       bne.s    locret_1314E
       cmpi.w    #-$400,d0
       bgt.s    locret_1314E
       move.b    #id_Stop,obAnim(a0) ; use "stopping" animation
       bset    #0,obStatus(a0)
       move.w    #sfx_Skid,d0
       jsr    (PlaySound_Special).l    ; play stopping sound
locret_1314E:
       rts 
; End of function Sonic_MoveRight

And replace it with this one:

Code:

; ||||||||||||||| S U B    R O U T    I N E |||||||||||||||||||||||||||||||||||||||
Sonic_MoveLeft:           ; XREF: Sonic_Move
       move.w    $14(a0),d0
       beq.s    loc_13086
       bpl.s    loc_130B2
loc_13086:
       bset    #0,$22(a0)
       bne.s    loc_1309A
       bclr    #5,$22(a0)
       move.b    #1,$1D(a0)
loc_1309A:
       sub.w    d5,d0
       move.w    d6,d1
       neg.w    d1
       cmp.w    d1,d0
       bgt.s    loc_130A6
       add.w    d5,d0
       cmp.w    d1,d0
       ble.s    loc_130A6
       move.w    d1,d0
loc_130A6:
       move.w    d0,obInertia(a0)
       move.b    #id_Walk,obAnim(a0) ; use walking animation
       rts
; ===========================================================================
loc_130B2:
       sub.w    d4,d0
       bcc.s    loc_130BA
       move.w    #-$80,d0
loc_130BA:
       move.w    d0,obInertia(a0)
       move.b    obAngle(a0),d0
       addi.b    #$20,d0
       andi.b    #$C0,d0
       bne.s    locret_130E8
       cmpi.w    #$400,d0
       blt.s    locret_130E8
       move.b    #id_Stop,obAnim(a0) ; use "stopping" animation
       bclr    #0,obStatus(a0)
       move.w    #sfx_Skid,d0
       jsr    (PlaySound_Special).l    ; play stopping sound
locret_130E8:
       rts 
; End of function Sonic_MoveLeft
; ||||||||||||||| S U B    R O U T    I N E |||||||||||||||||||||||||||||||||||||||
Sonic_MoveRight:       ; XREF: Sonic_Move
       move.w    $14(a0),d0
       bmi.s    loc_13118
       bclr    #0,$22(a0)
       beq.s    loc_13104
       bclr    #5,$22(a0)
       move.b    #1,$1D(a0)
loc_13104:
       add.w    d5,d0
       cmp.w    d6,d0
       blt.s    loc_1310C
       sub.w    d5,d0
       cmp.w    d6,d0
       bge.s    loc_1310C
       move.w    d6,d0
loc_1310C:
       move.w    d0,obInertia(a0)
       move.b    #id_Walk,obAnim(a0) ; use walking animation
       rts
; ===========================================================================
loc_13118:
       add.w    d4,d0
       bcc.s    loc_13120
       move.w    #$80,d0
loc_13120:
       move.w    d0,obInertia(a0)
       move.b    obAngle(a0),d0
       addi.b    #$20,d0
       andi.b    #$C0,d0
       bne.s    locret_1314E
       cmpi.w    #-$400,d0
       bgt.s    locret_1314E
       move.b    #id_Stop,obAnim(a0) ; use "stopping" animation
       bset    #0,obStatus(a0)
       move.w    #sfx_Skid,d0
       jsr    (PlaySound_Special).l    ; play stopping sound
       move.b  #6,($FFFFD1E4).w    ; set the spin dash dust routine to skid dust
       move.b  #$15,($FFFFD1DA).w
locret_1314E:
       rts 
; End of function Sonic_MoveRight

Now go to "_IncObj/ Sonic JumpDirection.asm" And replace all the code with this:

Code:

; ---------------------------------------------------------------------------
; Subroutine to    change Sonic's direction while jumping
; ---------------------------------------------------------------------------
; ||||||||||||||| S U B    R O U T    I N E |||||||||||||||||||||||||||||||||||||||
Sonic_JumpDirection:
       move.w    (v_sonspeedmax).w,d6
       move.w    (v_sonspeedacc).w,d5
       asl.w    #1,d5
       btst    #4,obStatus(a0)
       bne.s    Obj01_ResetScr2
       move.w    obVelX(a0),d0
       btst    #bitL,(v_jpadhold2).w ; is left being pressed?
       beq.s    loc_13278    ; if not, branch
       bset    #0,obStatus(a0)
       sub.w    d5,d0
       move.w    d6,d1
       neg.w    d1
       cmp.w    d1,d0
       bgt.s    loc_13278
       add.w    d5,d0        ; +++ remove this frame's acceleration change
       cmp.w    d1,d0        ; +++ compare speed with top speed
       ble.s    loc_13278    ; +++ if speed was already greater than the maximum, branch
       move.w    d1,d0
loc_13278:
       btst    #bitR,(v_jpadhold2).w ; is right being pressed?
       beq.s    Obj01_JumpMove    ; if not, branch
       bclr    #0,obStatus(a0)
       add.w    d5,d0
       cmp.w    d6,d0
       blt.s    Obj01_JumpMove
       sub.w    d5,d0        ; +++ remove this frame's acceleration change
       cmp.w    d6,d0        ; +++ compare speed with top speed
       bge.s    Obj01_JumpMove    ; +++ if speed was already greater than the maximum, branch
       move.w    d6,d0
Obj01_JumpMove:
       move.w    d0,obVelX(a0)    ; change Sonic's horizontal speed
Obj01_ResetScr2:
       cmpi.w    #$60,(v_lookshift).w ; is the screen in its default position?
       beq.s    loc_132A4    ; if yes, branch
       bcc.s    loc_132A0
       addq.w    #4,(v_lookshift).w
loc_132A0:
       subq.w    #2,(v_lookshift).w
loc_132A4:
       cmpi.w    #-$400,obVelY(a0) ; is Sonic moving faster than -$400 upwards?
       bcs.s    locret_132D2    ; if yes, branch
       move.w    obVelX(a0),d0
       move.w    d0,d1
       asr.w    #5,d1
       beq.s    locret_132D2
       bmi.s    loc_132C6
       sub.w    d1,d0
       bcc.s    loc_132C0
       move.w    #0,d0
loc_132C0:
       move.w    d0,obVelX(a0)
       rts 
; ===========================================================================
loc_132C6:
       sub.w    d1,d0
       bcs.s    loc_132CE
       move.w    #0,d0
loc_132CE:
       move.w    d0,obVelX(a0)
locret_132D2:
       rts 
; End of function Sonic_JumpDirection

The result should be something like this:

Spoiler: Result (My ROM Hack as an example)

I hope this helped! Thank you!

 

HOW TO EDIT THE TIME DELAY ON END OF ACT BEFORE SCORES GETTING ADDED ON SONIC 1


Note:this is designed for hivebrain's 2005 disassembler.Github users won't have a hard time making it work on their disassembler.

Another note:This is my first tutorial so if there are errors,tell me in the comments

First,go to loc_C61A(loc_C86C for special stage) and you should see something like this:

Code:

loc_C61A:                ; XREF: Obj3A_ChkPos
        cmpi.b    #$E,($FFFFD724).w
        beq.s    loc_C610
        cmpi.b    #4,$1A(a0)
        bne.s    loc_C5FE
        addq.b    #2,$24(a0)
        move.w    #180,$1E(a0)    ; set time delay to 3 seconds

and special stages code:

Code:

loc_C86C:                ; XREF: Obj7E_ChkPos
        cmpi.b    #2,$1A(a0)
        bne.s    loc_C85A
        addq.b    #2,$24(a0)
        move.w    #180,$1E(a0)    ; set time delay to 3 seconds
        move.b    #$7F,($FFFFD800).w ; load chaos    emerald    object

take a look at this code:

Code:

move.w    #180,$1E(a0)    ; set time delay to 3 seconds

You see the 180 number?It works like fps aka frames per second,a second is 60 frame per second
For example:if i want points to get added to score 1 second after the sign stops,i must replace 180 with 60.
another example:if i want the points get added to score 10 seconds after sign stops,i must replace 60 with 600.
a second:60
two seconds:120
three seconds:180
.
.
.
It goes 60 by 60
you get the idea

Bonus:HOWEVER if you want points gets added to score AFTER music stops instantly,do these two steps

1st:For GHZ,MZ,SYZ,LZ,SLZ and SBZ
Go to loc_C61A and change

Code:

move.w    #180,$1E(a0)    ; set time delay to 3 seconds

to:

Code:

move.w    #270,$1E(a0)    ; set time delay to 4,5 seconds

2nd:For Special Stages
go to loc_C86C and change

Code:

move.w    #180,$1E(a0)    ; set time delay to 3 seconds

to:

Code:

move.w    #320,$1E(a0)    ; set time delay to 5 seconds

there you have it!

A little note to the developers who changed the end of act music:This tutorial is very useful if you can't figure out how to change the time delay

edit:Sorry for bad english

 

HOW TO DISABLE (And enable) PALETTE CYCLES IN SONIC 1
This guide is for sonic 1 github users.
So, you want to disable or enable palette cycle?
This mini-guide is for you.
First of all, go to _Inc/PaletteCycle and go to any pal cycle of the level you want, for example:
PalCycle_MZ ; Marble Zone

For this tutorial im going to use MZ and GHZ as main examples.
We start with enable them, one thing I do to do it, Is that I copy the code and I adapt it for the another level.
If you dont know what Im talking about, here is what im trying to say:

Code:

PalCycle_MZ:
        lea    (Pal_MZCyc).l,a0
PCycMZ_Go:
        subq.w    #2,(v_pcyc_time).w ; decrement timer
        bpl.s    PCycMZ_Skip    ; if time remains, branch
        move.w    #5,(v_pcyc_time).w ; reset timer to 5 frames
        move.w    (v_pcyc_num).w,d0 ; get cycle number
        addq.w    #1,(v_pcyc_num).w ; increment cycle number
        andi.w    #3,d0        ; if cycle > 3, reset to 0
        lsl.w    #3,d0
        lea    (v_palette+$50).w,a1
        move.l    (a0,d0.w),(a1)+
        move.l    4(a0,d0.w),(a1)    ; copy palette data to RAM
PCycMZ_Skip:
        rts  
; End of function PalCycle_MZ

And now, lets try it in game:

It works!
But... now how I can disable one?
Easy, delete the whole code of the cycle routine and just add an rts under the main line, something like this:

Code:

PalCycle_GHZ:
        rts   

And taraaa!

You disabled it!
This guide works if you want new stuff for the game, specially new game art, because a problem I haved is that when I port the palette of an level, it was confusing with the pal cycle, thats why I decided to do the guide lol.

Anyway, see ya another time!
I hope this helped.

 

This is a very odd way of doing this.

Code:

PalCycle_Index:    dc.w PalCycle_GHZ-PalCycle_Index
        dc.w PalCycle_LZ-PalCycle_Index
        dc.w PalCycle_MZ-PalCycle_Index
        dc.w PalCycle_SLZ-PalCycle_Index
        dc.w PalCycle_SYZ-PalCycle_Index
        dc.w PalCycle_SBZ-PalCycle_Index
        zonewarning PalCycle_Index,2
        dc.w PalCycle_GHZ-PalCycle_Index    ; Ending

You could make a blank routine (or just use marble zone's stock routine), and make these calls jump there instead of destroying the entire palette cycle code.

 

This is the first tutorial, which is to
put a code to select the stage with one movement
It is very easy. Follow along with me. Put any movement you want. It is easy. Go to Sonic.asm and search for this LevSelCode_J

Code:

LevSelCode_J: if Revision=0
  dc.b btnUp,btnDn,btnL,btnR,0,$FF
  else
  dc.b btnUp,btnDn,btnDn,btnDn,btnL,btnR,0,$FF
  endc
  even

LevSelCode_US: dc.b btnUp,btnDn,btnL,btnR,0,$FF
  even

Did you know that btndown is the code that gives you a level selection and all we have to do now is delete the buttons and leave only one button, otherwise it will not work. USA was not used. As for those who use JP, they do the same thing like this.

Code:

LevSelCode_J: if Revision=0
  dc.b btnUp,0,$FF
  else
  dc.b btnUp,0,$FF
  endc
  even

LevSelCode_US: dc.b btnUp,0,$FF
  even

This lesson is short if you follow all of this it will work for you correctly.

Mod Edit: Fixed your code tags.

 

Try to type the following shown below.

Code:

LevSelCode_J:    if Revision=0
        dc.b btnUp,btnDn,btnL,btnR,0,$FF
        else
        dc.b btnUp,btnDn,btnDn,btnDn,btnL,btnR,0,$FF
        endif
        even

LevSelCode_US:    dc.b btnUp,btnDn,btnL,btnR,0,$FF
        even

Code:

LevSelCode_J:    if Revision=0
        dc.b btnUp,0,$FF
        else
        dc.b btnUp,0,$FF
        endif
        even

LevSelCode_US:    dc.b btnUp,0,$FF
        even

And no double-posting, please?

 

So... hi again...
What's up?
I remembed, these questions about this error:

This is going to use the DMA showed in the Spindash guide, so, thanks to Puto and JGMR, withouth them, this can't be possible.
So lets start.
Create a new asm file in _Inc folder, you can put any name, for this tutorial, we are going to name the file as "DMA Queue", and in it, paste this:

Code:

DMA_68KtoVRAM:                ; CODE XREF: LoadSonicDynPLC+48?p
                   ; LoadTailsDynPLC+48?p ...
       movea.l    ($FFFFD3EE).w,a1
       cmpa.w    #$D3EE,a1
       beq.s    DMA_68KtoVRAM_NoDMA
       move.w    #$9300,d0
       move.b    d3,d0
       move.w    d0,(a1)+
       move.w    #$9400,d0
       lsr.w    #8,d3
       move.b    d3,d0
       move.w    d0,(a1)+
       move.w    #$9500,d0
       lsr.l    #1,d1
       move.b    d1,d0
       move.w    d0,(a1)+
       move.w    #$9600,d0
       lsr.l    #8,d1
       move.b    d1,d0
       move.w    d0,(a1)+
       move.w    #$9700,d0
       lsr.l    #8,d1
       move.b    d1,d0
       move.w    d0,(a1)+
       andi.l    #$FFFF,d2
       lsl.l    #2,d2
       lsr.w    #2,d2
       swap    d2
       ori.l    #$40000080,d2
       move.l    d2,(a1)+
       move.l    a1,($FFFFD3EE).w
       cmpa.w    #$D3EE,a1
       beq.s    DMA_68KtoVRAM_NoDMA
       move.w    #0,(a1)

DMA_68KtoVRAM_NoDMA:            ; CODE XREF: DMA_68KtoVRAM+8?j
                   ; DMA_68KtoVRAM+56?j
       rts
; End of function DMA_68KtoVRAM


; ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ S U B    R O U T    I N E ÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛÛ


Process_DMA:                ; CODE XREF: ROM:00000D9C?p
                   ; ROM:00000E84?p ...
       lea    ($C00004).l,a5
       lea    ($FFFFD3C2).w,a1

Process_DMA_Loop:            ; CODE XREF: Process_DMA+20?j
       move.w    (a1)+,d0
       beq.s    Process_DMA_End
       move.w    d0,(a5)
       move.w    (a1)+,(a5)
       move.w    (a1)+,(a5)
       move.w    (a1)+,(a5)
       move.w    (a1)+,(a5)
       move.w    (a1)+,(a5)
       move.w    (a1)+,(a5)
       cmpa.w    #$D3EE,a1
       bne.s    Process_DMA_Loop

Process_DMA_End:            ; CODE XREF: Process_DMA+C?j
       move.w    #0,($FFFFD3C2).w
       move.l    #$FFFFD3C2,($FFFFD3EE).w
       rts
; End of function Process_DMA

Thanks to Puto and JGMR for the code
Now, go to "sonic.asm" and paste it below TilemapToVRAM and above include "_inc/Nemesis Decompression.asm", include the file:

Code:

; End of function TilemapToVRAM

       include    "_inc/DMA Queue.asm"    ; <-- add this line!
       include    "_inc/Nemesis Decompression.asm"

Now, go to .nochg located under the VBla_08 routine, and add these two lines at the beginning:

Code:

       move.w    #$83,(v_vdp_buffer2).w
       jsr    (Process_DMA).l¨

The queue should now be working.
Thats all for now!
If I forgot to do something on this tutorial, let me know to update it.

PeanutNoceda: The guide
Really Special Thanks to: Puto and JGMR

 

How to make S monitor add 50 rings.
First, you need to go _incObj\2E Monitor Content Power-Up.asm, you will find this:

Replace this:

Code:

Pow_ChkS:
        cmpi.b    #7,d0        ; does monitor contain 'S'?
        bne.s    Pow_ChkEnd
        nop  

With this:

Code:

Pow_ChkS:
        cmpi.b    #7,d0        ; does monitor contain 'S'?
        bne.s    Pow_ChkS

        addi.w    #50,(v_rings).w    ; add 50 rings to the number of rings you have
        ori.b    #1,(f_ringcount).w ; update the ring counter
        cmpi.w    #100,(v_rings).w ; check if you have 100 rings
        bcs.s    Pow_RingSound
        bset    #1,(v_lifecount).w
        beq.w    ExtraLife
        cmpi.w    #200,(v_rings).w ; check if you have 200 rings
        bcs.s    Pow_RingSound
        bset    #2,(v_lifecount).w
        beq.w    ExtraLife

I hope this helped.

 

How to extend Sonic 1 Debug Mode by using ASM68k​

First, you can do it with zone you want to make the items extended. If the monitor no image is not enough for debug mode, you can replace it with another ID.
Go to the Sonic 1 ASM68k root and _inc\DebugList.asm

You will see all of debug mode set of the items that display on debug mode, you can do it with levels.
If you want to extend monitor slots, you can make it full like how it is on Sonic 3 Complete (Sonic 1 Mobile).

Replace this:

Code:

    dbug    Map_Monitor,    id_Monitor,    0,    0,    $680

With this:

Code:

    dbug    Map_Monitor,    id_Monitor,    0,    0,    $680 ; Empty
    dbug    Map_Monitor,    id_Monitor,    1,    3,    $680 ; Eggman
    dbug    Map_Monitor,    id_Monitor,    2,    4,    $680 ; Sonic 1UP
    dbug    Map_Monitor,    id_Monitor,    3,    5,    $680 ; Speed Shoes
    dbug    Map_Monitor,    id_Monitor,    4,    6,    $680 ; Shield
    dbug    Map_Monitor,    id_Monitor,    5,    7,    $680 ; Invincibility
    dbug    Map_Monitor,    id_Monitor,    6,    8,    $680 ; 10 rings
    dbug    Map_Monitor,    id_Monitor,    7,    9,    $680 ; S Monitor
    dbug    Map_Monitor,    id_Monitor,    8,    10,    $680 ; Goggles
    dbug    Map_Monitor,    id_Monitor,    9,    11,    $680 ; Broken

Better order and Sonic 3 Inspiration:

Code:

    dbug    Map_Monitor,    id_Monitor,    7,    9,    $680 ; S Monitor
    dbug    Map_Monitor,    id_Monitor,    6,    8,    $680 ; 10 rings
    dbug    Map_Monitor,    id_Monitor,    4,    6,    $680 ; Shield
    dbug    Map_Monitor,    id_Monitor,    3,    5,    $680 ; Speed Shoes
    dbug    Map_Monitor,    id_Monitor,    5,    7,    $680 ; Invincibility
    dbug    Map_Monitor,    id_Monitor,    2,    4,    $680 ; Sonic 1UP
    dbug    Map_Monitor,    id_Monitor,    1,    3,    $680 ; Eggman
    dbug    Map_Monitor,    id_Monitor,    8,    10,    $680 ; Goggles

Before you ask me, if you want to extend the hidden bonus. It has 3 frames, you should do something like this:

Code:

    dbug    Map_Bonus,    id_HiddenBonus,    3,    3,    $84B6
    dbug    Map_Bonus,    id_HiddenBonus,    2,    2,    $84B6
    dbug    Map_Bonus,    id_HiddenBonus,    1,    1,    $84B6

If you want to include Signpost and Egg Prison just like in Sonic Mania or Sonic RSDK, you can follow this code in any zone you want to add:

Code:

    dbug    Map_Sign,    id_Signpost,    0,    0,    $0D00  
    dbug    Map_Pri,    id_Prison,    2,    2,    $3E00
    dbug    Map_Pri,    id_Prison,    1,    1,    $3E00

I hope this helped you by extending your ROM Hack Debug Mode, I hope this will be the same method for Sonic 2 and Sonic 3 soon.

 

How to Remove the Checksum Check

I was surprised a quick guide for this didn't exist yet. This is a pretty simple one, but still handy. It's one of the first things I do whenever I start a new hacking project.

So, you might know how making ROM hacks requires a tool to fix the checksum in the ROM's header, otherwise you'll run into a pure red screen and the game won't boot up. In the ASM68K disassembly that tool is called fixheadr.exe and in the AS version it's the command common.fix_header inside the build.lua script.

Well, not only can we get rid off the need to use any of these tools, we can also save a few seconds of the game doing the painfully slow checksum check each time we boot up our game! It really saves a lot of time over a long development session and countless test builds.

Doing this is as simple as removing the check aptly named CheckSumCheck near the start of the game. Just delete every line marked with an X:

Code:

GameProgram:
		tst.w	(vdp_control_port).l
		btst	#6,(z80_expansion_control+1).l
		beq.s	CheckSumCheck
		cmpi.l	#'init',(v_init).w ; has checksum routine already run?
		beq.w	GameInit	; if yes, branch

CheckSumCheck:
X		movea.l	#EndOfHeader,a0	; start checking bytes after the header	($200)
X		movea.l	#RomEndLoc,a1	; stop at end of ROM
X		move.l	(a1),d0
X		moveq	#0,d1
X
X.loop:
X		add.w	(a0)+,d1
X		cmp.l	a0,d0
X		bhs.s	.loop
X		movea.l	#Checksum,a1	; read the checksum
X		cmp.w	(a1),d1		; compare checksum in header to ROM
X		bne.w	CheckSumError	; if they don't match, branch

CheckSumOk:

That's it! For some extra cleanup, you can also remove the CheckSumError routine a bit further down below, since it's now obsolete code.