Sonic the Hedgehog CD/MMD Tweaking

SCHG: Sonic the Hedgehog CD
Main Article
File Locations
File Locations
Art Editing
Editing Art Nemesis Format Art MMDs, A-P Palmtree Panic MMDs Collision Chaos MMDs Tidal Tempest MMDs Quartz Quadrant MMDs Wacky Workbench MMDs Stardust Speedway MMDs Metallic Madness MMDs MMDs, S-W
MMD Tweaking
Tweaking MMDs Maximum rings allowed Minimum rings for Giant Ring Rings given by ring Rings given by Ring Monitor Invincibility duration Super Sneakers duration Regular speed stats Super Sneakers speed stats
RAM Editing
RAM Editing

Here are some locations in a European Sonic CD level MMD which contain tweakable code (in Motorola 68000 assembly).

Maximum rings allowed

$AEFA:
	move.w	($FF1512).l,d1	; Move number of rings into d1
	cmpi.w	#$3E8,d1	; Compare $3E8 (1000) with d1 (number of rings)
	bcs.s	loc_20AF10	; If the number of rings is < 1000, branch
	move.w	#$3E7,d1	; Move $3E7 (999) into d1
	move.w	d1,($FF1512).l	; Move d1 back to the address where the number of rings is at

Minimum rings for Giant Ring

$D50C:
	cmpi.w	#$32,($FF1512).l	; Compare 50 with the number of rings
	bcc.s	loc_20D51C	; If number of rings >= 50, allow entrance to the special stage.
	jmp	sub_20788C	; Otherwise jump here

Rings given by ring

$9F1A:
	addq.w	#1,($FF1512).l	; Add 1 to number of rings

Rings given by Ring Monitor

$A88E:
	addi.w	#$A,($FF1512).l	; Add 10 to the current number of rings

Invincibility duration

$A8F8:
	move.b	#1,($FF151F).l	; Enable invicibility
	move.w	#$4B0,($FFFFD032).w	; Set the invincibility duration time to $4B0

Super Sneakers duration

$A95A:
	move.b	#1,($FF1520).l	; Enable super sneakers
	move.w	#$4B0,($FFFFD034).w	; Set the super sneakers duration time to $4B0

Regular speed stats

$4082:
	move.w	#$600,($FFFFF760).w	; Maximum velocity
	move.w	#$C,($FFFFF762).w	; Maximum acceleration

Super Sneakers speed stats

$A968:
	move.w	#$C00,($FFFFF760).w	; Set maximum velocity to $C00
	move.w	#$18,($FFFFF762).w	; Set maximum acceleration to $18