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Difference between revisions of "SCHG:Sonic the Hedgehog 3 & Knuckles"

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m (Main System Memory Locations)
m (Black Squirrel moved page SCHG:Sonic 3 & Knuckles to SCHG:Sonic the Hedgehog 3 & Knuckles: Text replacement - "Sonic 3 & Knuckles" to "Sonic the Hedgehog 3 & Knuckles")
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__NOTOC__
Note: As S3&K is a "lock-on" game, all offsets below $200000 are in the base S&K ROM, and all offsets above $200000 are in the connected S3 ROM.
+
{{SCHG S3K}}
==ROM Hacking==
+
This is the '''[[Sonic Community Hacking Guide]] for ''[[Sonic 3 & Knuckles]]'''''. As ''Sonic 3 & Knuckles'' is a "[[Lock-On Technology|lock-on]]" game, all offsets below $200000 are in the base ''[[Sonic & Knuckles]]'' ROM, and all offsets above $200000 are in the connected ''[[Sonic the Hedgehog 3]]'' ROM. Since ''Sonic 3 & Knuckles'' runs on ''Sonic & Knuckles''<nowiki>'</nowiki> engine, all the information on this page also applies to ''Sonic & Knuckles'' alone, with the exception of any pointers above $200000 (which are part of the locked-on ''Sonic 3'' ROM).
===Art Editing===
 
====Uncompressed Art Locations====
 
  
====[[Nemesis compression|Nemesis Compressed]] Art Locations====
 
  
====[[Kosinski compression|Kosinski Compressed]] Art Locations====
 
 
====Palette Editing====
 
Usually, it's not really necessary to edit a palette in hex. Palette editors give you instant feedback for each RGB value, and the palette can be easily saved as a separate binary and reimported into the ROM. However, it is sometimes desirable or necessary to do it in hex, and it can't hurt to know how it's done.
 
 
These are the ROM offsets of the palettes in ''Sonic 3 and Knuckles'', as listed by [[HivePal]]:
 
{| border="1"
 
!Offset||Name
 
|-
 
|291A
 
|Angel Island Act 1 Cycle #1
 
|-
 
|293A
 
|Angel Island Act 1 Cycle #2
 
|-
 
|29BA
 
|Angel Island Act 1 Cycle #3
 
|-
 
|2A1A
 
|Angel Island Act 1 Cycle #4
 
|-
 
|2A4A
 
|Angel Island Act 2 Cycle #1
 
|-
 
|2A6A
 
|Angel Island Act 2 Cycle #2
 
|-
 
|2A9A
 
|Angel Island Act 2 Cycle #3
 
|-
 
|2ACA
 
|Angel Island Act 2 Cycle #4
 
|-
 
|2B32
 
|Hydrocity Act 1 Cycle
 
|-
 
|2B52
 
|Carnival Night Cycle #1
 
|-
 
|2BB2
 
|Carnival Night Cycle #2
 
|-
 
|2C32
 
|Carnival Night Cycle #3
 
|-
 
|2C66
 
|Carnival Night Cycle #4
 
|-
 
|2CA6
 
|Carnival Night Cycle #5
 
|-
 
|2D06
 
|Carnival Night Cycle #6
 
|-
 
|2D86
 
|Carnival Night Cycle #7
 
|-
 
|2DFA
 
|Icecap Cycle #1
 
|-
 
|2E3A
 
|Icecap Cycle #2
 
|-
 
|2E82
 
|Icecap Cycle #3
 
|-
 
|2E9A
 
|Icecap Cycle #4
 
|-
 
|2EDA
 
|Launch Base Act 1 Cycle
 
|-
 
|2EEC
 
|Launch Base Act 2 Cycle
 
|-
 
|2EFE
 
|Lost Level 09 Act 1 Cycle #1
 
|-
 
|2F7E
 
|Lost Level 09 Act 1 Cycle #2
 
|-
 
|2FA2
 
|2P Level - Balloon Park Cycle #1
 
|-
 
|2FB4
 
|2P Level - Balloon Park Cycle #2
 
|-
 
|3032
 
|2P Level - Desert Palace Cycle
 
|-
 
|3082
 
|2P Level - Endless Mine Cycle #1
 
|-
 
|30BE
 
|2P Level - Endless Mine Cycle #2
 
|-
 
|31C2
 
|Super Sonic
 
|-
 
|31FE
 
|Super Sonic Underwater
 
|-
 
|323A
 
|Super Sonic Underwater
 
|-
 
|3C78
 
|Sega Logo #1
 
|-
 
|3CF8
 
|Sega Logo #2
 
|-
 
|3D08
 
|Intro Frame #1
 
|-
 
|3D48
 
|Intro Frame #2
 
|-
 
|3D88
 
|Intro Frame #3
 
|-
 
|3DC8
 
|Intro Frame #4
 
|-
 
|3E08
 
|Intro Frame #5
 
|-
 
|3E48
 
|Intro Frame #6
 
|-
 
|3E88
 
|Title Screen
 
|-
 
|3FD4
 
|Title Screen Cycle
 
|-
 
|5092
 
|2P Level - Knuckles
 
|-
 
|70BC
 
|Level Select Menu - EHZ Icon
 
|-
 
|70DC
 
|Level Select Menu - MZ Icon
 
|-
 
|70FC
 
|Level Select Menu - HTZ Icon
 
|-
 
|711C
 
|Level Select Menu - HPZ Icon
 
|-
 
|713C
 
|Level Select Menu - OOZ Icon
 
|-
 
|715C
 
|Level Select Menu - MCZ Icon
 
|-
 
|717C
 
|Level Select Menu - CNZ Icon
 
|-
 
|719C
 
|Level Select Menu - CPZ Icon
 
|-
 
|71BC
 
|Level Select Menu - ARZ Icon
 
|-
 
|71DC
 
|Level Select Menu - SCZ Icon
 
|-
 
|71FC
 
|Level Select Menu - WFZ Icon
 
|-
 
|721C
 
|Level Select Menu - DEZ Icon
 
|-
 
|723C
 
|Level Select Menu - Special Stage Icon
 
|-
 
|725C
 
|Level Select Menu - X Icon
 
|-
 
|727C
 
|Level Select Menu - Sound Test Icon
 
|-
 
|7A26
 
|Special Stage - Sonic and Tails
 
|-
 
|7A66
 
|Special Stages
 
|-
 
|7AA6
 
|Special Stage 1
 
|-
 
|7ACC
 
|Special Stage 2
 
|-
 
|7AF2
 
|Special Stage 3
 
|-
 
|7B18
 
|Special Stage 4
 
|-
 
|7B3E
 
|Special Stage 5
 
|-
 
|7B64
 
|Special Stage 6
 
|-
 
|7B8A
 
|Special Stage 7
 
|-
 
|7BB0
 
|Special Stage 8
 
|-
 
|A55E
 
|2P Menu - Sonic and Tails
 
|-
 
|A57E
 
|2P Menu - Knuckles
 
|-
 
|A59E
 
|2P Menu - Unselected Portraits
 
|-
 
|A5BE
 
|2P Menu - ALZ Portrait
 
|-
 
|A5DE
 
|2P Menu - BPZ Portrait
 
|-
 
|A5FE
 
|2P Menu - CGZ Portrait
 
|-
 
|A61E
 
|2P Menu - DPZ Portrait
 
|-
 
|A63E
 
|2P Menu - EMZ Portrait
 
|-
 
|BBB6
 
|Data Select - Sonic/Tails/Knuckles/Emeralds
 
|-
 
|BBF6
 
|Data Select - Sonic Portrait
 
|-
 
|BC16
 
|Data Select - Super Sonic Portrait
 
|-
 
|BC36
 
|Data Select - AIZ Portrait
 
|-
 
|BC56
 
|Data Select - HCZ Portrait
 
|-
 
|BC76
 
|Data Select - MGZ Portrait
 
|-
 
|BC96
 
|Data Select - CNZ Portrait
 
|-
 
|BCB6
 
|Data Select - FBZ Portrait (Unused)
 
|-
 
|BCD6
 
|Data Select - ICZ Portrait
 
|-
 
|BCF6
 
|Data Select - LBZ Portrait
 
|-
 
|236AC
 
|Red Balls Debug Mode Item
 
|-
 
|2D3BE
 
|Special Stage Results
 
|-
 
|4160A
 
|Ending - Credits
 
|-
 
|4168A
 
|Ending - Knuckles and Eggman
 
|-
 
|457AE
 
|Knuckles
 
|-
 
|457CE
 
|###
 
|-
 
|4580E
 
|Carnival Night Lights Off
 
|-
 
|45E86
 
|Angel Island Act 1 Intro - Emeralds
 
|-
 
|47092
 
|Angel Island Act 1 Boss
 
|-
 
|47CD6
 
|Angel Island Act 2 Boss
 
|-
 
|48C9A
 
|Hydrocity Act 1 Boss
 
|-
 
|49D52
 
|Hydrocity Act 2 Boss
 
|-
 
|4B588
 
|Marble Garden Act 2 Boss
 
|-
 
|4BF70
 
|Carnival Night Act 1 Boss
 
|-
 
|4C91E
 
|Carnival Night Act 2 Boss
 
|-
 
|4D520
 
|Flying Battery Act 1 Boss
 
|-
 
|4DB80
 
|Flying Battery Act 2 Boss
 
|-
 
|4EBC2
 
|Icecap Act 2 Boss
 
|-
 
|4F444
 
|Icecap Act 1 Boss
 
|-
 
|4F98C
 
|Launch Base Act 1 Boss
 
|-
 
|503EE
 
|Launch Base Act 2 Triplet Boss
 
|-
 
|50C8A
 
|Launch Base Act 2 Cannonball Boss
 
|-
 
|520DC
 
|Launch Base Act 2 Final Boss
 
|-
 
|5211C
 
|Ending - Sonic
 
|-
 
|5213C
 
|Ending - Tails
 
|-
 
|5215C
 
|Ending - Super Sonic
 
|-
 
|8C234
 
|Sonic and Tails
 
|-
 
|8C274
 
|Level Select Menu
 
|-
 
|8C314
 
|Angel Island Act 1
 
|-
 
|8C374
 
|Angel Island Act 1 Intro
 
|-
 
|8C3D4
 
|Angel Island Act 2
 
|-
 
|8C494
 
|Angel Island Act 1 Underwater
 
|-
 
|8C434
 
|Angel Island Act 2 FBZ Sequence
 
|-
 
|8C514
 
|Angel Island Act 2 Underwater
 
|-
 
|8C594
 
|Hydrocity Act 1
 
|-
 
|8C654
 
|Hydrocity Act 1 Underwater
 
|-
 
|8C5F4
 
|Hydrocity Act 2
 
|-
 
|8C6D4
 
|Hydrocity Act 2 Underwater
 
|-
 
|8C754
 
|Marble Garden
 
|-
 
|8C7B4
 
|Carnival Night
 
|-
 
|8C814
 
|Carnival Night Underwater
 
|-
 
|8C894
 
|Icecap Act 1
 
|-
 
|8C8F4
 
|Icecap Act 2
 
|-
 
|8C954
 
|Icecap Act 2 Underwater
 
|-
 
|8C9D4
 
|Launch Base Act 1
 
|-
 
|8CA34
 
|Launch Base Act 2
 
|-
 
|8CA94
 
|Launch Base Act Underwater
 
|-
 
|8CB74
 
|2P Level - Azure Lake
 
|-
 
|8CBD4
 
|2P Level - Balloon Park
 
|-
 
|8CC94
 
|2P Level - Chrome Gadget
 
|-
 
|8CC34
 
|2P Level - Desert Palace
 
|-
 
|8CCF4
 
|2P Level - Endless Mine
 
|-
 
|8CD54
 
|Bonus Stage
 
|-
 
|A943C
 
|Mushroom Hill Act 1
 
|-
 
|A949C
 
|Mushroom Hill Act 2
 
|-
 
|A909C
 
|Flying Battery Act 1
 
|-
 
|A90FC
 
|Flying Battery Act 2
 
|-
 
|A94FC
 
|Sandopolis Act 1
 
|-
 
|A955C
 
|Sandopolis Act 2
 
|-
 
|A967C
 
|Lava Reef Act 1
 
|-
 
|A96DC
 
|Lava Reef Act 2
 
|-
 
|A9CDC
 
|Lava Reef Act 2 Boss
 
|-
 
|A9D3C
 
|Hidden Palace
 
|-
 
|A973C
 
|Sky Sanctuary Act 1
 
|-
 
|A979C
 
|Sky Sanctuary Act 2
 
|-
 
|A98BC
 
|Death Egg Act 1
 
|-
 
|A991C
 
|Death Egg Act 2
 
|-
 
|A9D9C
 
|Death Egg Act 2 Boss
 
|-
 
|A997C
 
|The Doomsday
 
|-
 
|164896
 
|Marble Garden Act 2 - Day to Night #1
 
|-
 
|164916
 
|Marble Garden Act 2 - Day to Night #2
 
|-
 
|164996
 
|Marble Garden Act 2 - Day to Night #3
 
|-
 
|164A16
 
|Marble Garden Act 2 - Day to Night #4
 
|-
 
|19D262
 
|Data Select - Background
 
|-
 
|19D282
 
|2P Menu - Background
 
|}
 
 
For information about the palette format, see [[Palette#Megadrive_Palette|Megadrive palette]].
 
 
====Pattern Load Cues====
 
 
===Object Editing===
 
====Object Pointer List====
 
 
====Sprite Mappings====
 
 
====Object Placement====
 
There are six bites in one object definition. The first two bytes are the X position of the object, and the next two bytes are the Y position. The 5th byte is the reference number on the object pointer list (see above), and the 6th byte is an optional declaration to use for defining that object's behavior and/or animation. This will depend on the object. See the level specific hacking info for the locations of the object lists.
 
 
The 6th byte, the object subtype, is loaded in the byte $2C of the SST of that object (see below).
 
 
===Ring Placement===
 
There are four bytes for every ring object. The first 2 bytes are X coordinates, and the next two are the Y coordinates. Sonic 3k uses individual rings, unlike Sonic 2, which uses ring groups that have to be expanded into RAM. The advantage of Sonic 3k's method is that ring position data can be read directly from ROM, meaning that only two bytes are used up in RAM per ring instead of six, saving on RAM space and allowing Sonic 3k levels to have a maximum of 511 rings, as compared to Sonic 2's 255, despite allocating $200 bytes less to the ring status table.
 
 
The ring placement data '''must''' start with 0000 0000, and '''must''' end with FFFF. These prevent the rings position checker subroutine from going over the bounds of the ring placement data, and are necessary for the correct functioning of the rings manager.
 
 
===Level Layout===
 
Level layouts are stored uncompressed in the ROM, and the format they use differs significantly from the format used in Sonic 2, allowing much larger levels.
 
 
The layout starts with an 8 byte header describing the layout. The first word of this header is the number of 128x128 tiles that make one foreground row, and the second word is the number of 128x128 tiles that make one background row. The third word is the number of foreground rows, and the fourth is the number of background rows.
 
 
Next is a list of 64 word-sized pointers in RAM. Each row of 128x128 tiles has two pointers - one for the foreground data and one for the background data. The maximum level height is thus (64 / 2 * 128) = $1000 pixels, double the maximum level height for Sonic 2.
 
 
The actual rows data (beginning at byte $88) is very simple - there is one byte per 128x128 tile, and the blocks are put together from left to right.
 
 
See the level specific hacking info for the locations of level layout data. (Put here for now, will eventually be moved to subpage)
 
{| border = "1"
 
! Offset ||Level Name
 
|-
 
| 2814A8
 
| Angel Island 1
 
|-
 
| 281CF4
 
| Angel Island 2
 
|-
 
| 282A5A
 
| Hydrocity 1
 
|-
 
| 283582
 
| Hydrocity 2
 
|-
 
| 28442A
 
| Marble Garden 1
 
|-
 
| 2850BA
 
| Marble Garden 2
 
|-
 
| 285E6A
 
| Carnival Night 1
 
|-
 
| 286A34
 
| Carnival Night 2
 
|-
 
| 2879C2
 
| Icecap 1
 
|-
 
| 28898A
 
| Icecap 2
 
|-
 
| 2897DA
 
| Launch Base 1
 
|-
 
| 28A786
 
| Launch Base 2
 
|-
 
| 09F43E
 
| Mushroom Hill 1
 
|-
 
| 0A0172
 
| Mushroom Hill 2
 
|-
 
| 09D708
 
| Flying Battery 1
 
|-
 
| 09D708
 
| Flying Battery 2
 
|-
 
| 0A0DE2
 
| Sandopolis 1
 
|-
 
| 0A1C4E
 
| Sandopolis 2
 
|-
 
| 0A2A66
 
| Lava Reef 1
 
|-
 
| 0A388E
 
| Lava Reef 2
 
|-
 
| 0A76F4
 
| Lava Reef 2 (Robotnik)
 
|-
 
| 0A79AC
 
| Hidden Palace
 
|-
 
| 0A4616
 
| Sky Sanctuary 1
 
|-
 
| 0A5286
 
| Sky Sanctuary 2
 
|-
 
| 0A5402
 
| Death Egg 1
 
|-
 
| 0A63D0
 
| Death Egg 2
 
|-
 
| 0A7FD4
 
| Death Egg 2 (Robotnik)
 
|-
 
| 0A725E
 
| Doomsday
 
|}
 
 
===16x16 Block Mappings===
 
 
===Text Editing===
 
 
==RAM Hacking==
 
 
===Main System Memory Locations===
 
This is a map of 68k memory as used by the main gameplay engine. Note that any numbers entered (for example, score or number of rings) will have to be converted to hex first.
 
 
These are the offsets in RAM. To convert them to Genecyst savestate offsets, add $2478.
 
{| border="1"
 
!RAM offset||Description
 
|-
 
| $0000-$7FFF
 
| 128x128 mappings
 
|-
 
| $8000-$8FFF
 
| Level layout
 
|-
 
| $9000-$A9FF
 
| 16x16 mappings
 
|-
 
| $AA00-$AFFF
 
| Pattern decompression buffer
 
|-
 
| $B000-$CFCB
 
| Object attribute table
 
|-
 
| $D000-????
 
| Kosinski decompression buffer
 
|-
 
| $E380
 
| Number of objects currently in collision response list, multiplied by 2.
 
|-
 
| $E382-$E3FF
 
| Collision response list. The format is one word per object, where the word is the starting address of the object's SST. Only objects in this list are processed by the collision response routine.
 
|-
 
| $E700-$EAFF
 
| Ring status table. The format is two bytes per ring, these bytes being 0000 while the ring has yet to be consumed, serving as a ring destruction timer while the ring is being consumed, and being set to FFFF when the ring has been fully consumed.
 
|-
 
| $EE12
 
| Screen Y end
 
|-
 
| $EE14
 
| Screen X start
 
|-
 
| $EE16
 
| Screen X end
 
|-
 
| $EE18
 
| Screen Y start
 
|-
 
| $EE1A
 
| Screen Y end location for Sonic; the maximum value for camera Y position. Like $EE12, but changes slowly instead of instantly when the level Y boundary changes.
 
|-
 
| $EE33
 
| Routine counter for Dynamic Screen Resizing. (Dynamic Level Events)
 
|-
 
| $EE42-$EE45
 
| Address (in the ROM) of the first ring whose X position is greater than or equal to the current camera X value minus 8.
 
|-
 
| $EE46-$EE49
 
| Address (in the ROM) of the first ring whose X position is greater than or equal to the current camera X value + $148.
 
|-
 
| $EE4A-$EE4B
 
| Address (in the ring status table) of the first ring whose X position is greater than or equal to the current camera X value minus 8.
 
|-
 
| $EE60
 
| Camera X for the second player in 2p mode
 
|-
 
| $EE64
 
| Camera Y for the second player in 2p mode
 
|-
 
| $EE68
 
| Copy of camera X for the second player in 2p mode for rasters
 
|-
 
| $EE6C
 
| Copy of camera Y for the second player in 2p mode for rasters
 
|-
 
| $EE78
 
| Camera X
 
|-
 
| $EE7C
 
| Camera Y
 
|-
 
| $EE80
 
| Copy of Camera X for Rasters
 
|-
 
| $EE84
 
| Copy of Camera Y for Rasters
 
|-
 
| $EEC6
 
| Level property (like killer wall in HCZ2 or avalanche in ICZ1)
 
|-
 
| $EF49
 
| Flag which determines whether the second player in a 2P versus game is player-controlled or just a "ghost" of the first player.
 
|-
 
| $EF72-$EF73
 
| Flag which is set to $FF00 if an ending is running. The only thing this seems to do is prevent the game from being able to pause.
 
|-
 
| $EF80
 
| The number of rings inside the ring consumption table.
 
|-
 
| $EF82-$EFFF
 
| Ring consumption table. Contains the RAM addresses (inside the ring status table) of rings which are currently being consumed. Once consumed, the rings are deleted from this table.
 
|-
 
| $F000-$F07F
 
| Second underwater palette.
 
|-
 
| $F080-$F0FF
 
| Underwater palette.
 
|-
 
| $F600
 
| Master level trigger. Tells the game what it should be doing.
 
The MSB is a loading routine flag. It only matters for some game modes. It won't have any effect when changing modes because it's filtered out, but the corresponding routine does pay attention to it...
 
|-
 
| $F602
 
| In-game Controller 1 held state. Same as F604, but it only updates during the main game loop, and not while paused, or a custcene is running.
 
|-
 
| $F603
 
| In-game Controller 1 pressed state. Same as F602, but only tells which buttons are being pressed newly this frame.
 
|-
 
| $F604
 
| This bitfield tells which button(s) on Controller 1, if any, are currently pressed. Format is:
 
*Bit 0 - Up
 
*Bit 1 - Down
 
*Bit 2 - Left
 
*Bit 3 - Right
 
*Bit 4 - B
 
*Bit 5 - C
 
*Bit 6 - A
 
*Bit 7 - Start
 
This is updated every frame.
 
|-
 
| $F605
 
| Same as $F604, but only tells which buttons are being pressed newly this frame.
 
|-
 
| $F606
 
| Same as $F604, but for Controller 2.
 
|-
 
| $F607
 
| Same as $F606, but only tells which buttons are being pressed newly this frame for Controller 2.
 
|-
 
| $F614
 
| Demo time left & Time until demo starts from title screen.
 
|-
 
| $F636
 
| RNG seed (used for pseudo-random number generation).
 
|-
 
| $F63A-$F63B
 
| Game paused flag.
 
|-
 
| $F648-$F649
 
| Current water level. Should be a valid Y-axis value. Remember, the top of the level is $0000.
 
|-
 
| $F64C
 
| Water on: seems to be a copy of $F730.
 
|-
 
| $F65E
 
| Super Sonic palette counter. Decremented with every frame. How it works, exactly, is not known.
 
|-
 
| $F65F
 
| Sets the rotating palette for Super Sonic.
 
|-
 
| $F66A
 
| In-game Controller 2 held state. Same as $F602, but for controller 2
 
|-
 
| $F66B
 
| In-game Controller 2 pressed state. Same as $F66A, but only tells which buttons are being pressed newly this frame.
 
|-
 
| $F670-$F671
 
| Super Sonic ring drain counter. This is updated each frame, so the counter is set to 60 ($3C) on consoles operating in 60Hz mode, or 50 ($32) in consoles operating in 50Hz mode. After each frame, the code subtracts 1. One ring is removed when this counter reaches zero; in other words, each second.
 
|-
 
| $F680
 
| A buffer for pattern loading cues (requests).
 
|-
 
| $F700-$F701
 
| Seems to be set to $0001 when in a Sonic & Tails game. Set to $0000 when not a Sonic & Tails game.
 
|-
 
| $F702-$F703
 
| Tails control counter. Counts how long until the CPU takes control.
 
|-
 
| $F704-$F705
 
| Tails repawn counter.
 
|-
 
| $F708-$F709
 
| Tails CPU routine.
 
|-
 
| $F70A-$F70B
 
| Tails CPU target X position. Tells Tails where Sonic's X position is so he can fly back to him.
 
|-
 
| $F70C-$F70D
 
| Tails CPU target Y position. Tells Tails where Sonic's Y position is so he can fly back to him.
 
|-
 
| $F70E-$F70F
 
| Tails interact ID. Object ID of last object Tails stood on.
 
|-
 
| $F710
 
| Routine counter for the rings manager.
 
|-
 
| $F711
 
| Level started flag. Set to 1 as soon as the player first gets control in the level.
 
|-
 
| $F730
 
| Water flag. Must be set for any of the other water variables to have any effect. Note that levels without water don't have an underwater palette; you must set one or everything below the water level will be black.
 
|-
 
| $F760-$F761
 
| Sonic's top speed
 
|-
 
| $F762-$F763
 
| Sonic's acceleration
 
|-
 
| $F764-$F765
 
| Sonic's deceleration
 
|-
 
| $F766
 
| Sonic's current mapping frame number.
 
|-
 
| $F7AA
 
| Seems to be clear during normal play, but set to some value during a boss fight. That value may be the current Zone number.
 
|-
 
| $F7C6
 
| Reverse gravity flag. Only in Sonic & Knuckles.
 
|-
 
| $F7CA
 
| Controller lock for controller 1.
 
|-
 
| $F7CB
 
| Controller lock for controller 2.
 
|-
 
| $F7D0-$F7D1
 
| Bonus counter. Increments upon destruction of a destroyable object, and is used to determine how many points the destruction should give. Resets when the player touches the ground.
 
|-
 
| $F7D2-$F7D3
 
| Time bonus counter at the end of level result screen
 
|-
 
| $F7D4-$F7D5
 
| Ring bonus counter at the end of level result screen
 
|-
 
| $F7DA-$F7DB
 
| Counts the number of times the camera has scrolled to the right by one full screen width from its previous position - initial value is $FF80 and then counts up like: $FF80,$0000,$0080,$0100,$0180,etc.
 
|-
 
| $FC00 - $FC7F
 
| Normal palette.
 
|-
 
| $FC80-$FCFF
 
| Second palette.
 
|-
 
| $FE00
 
| Start of the system stack. Note that the stack grows '''up''' rather than '''down'''. This means that when something is pushed onto the stack, the SP is decremented, and when something is popped from it, the SP is incremented.
 
|-
 
| $FE02-$FE03
 
| Level restart flag.
 
|-
 
| $FE06
 
| Object currently selected in debug mode.
 
|-
 
| $FE09
 
| Object placement mode flag.
 
|-
 
| $FE10
 
| The current Zone. This is the value assigned to the Zone, not its position in the level list.
 
|-
 
| $FE11
 
| Act number
 
|-
 
| $FE12
 
| Life Count
 
|-
 
| $FE18
 
| Number of continues.
 
|-
 
| $FE19
 
| Super Sonic flag. Setting this will load the Super Sonic tiles, adjust Sonic's jump height, and start draining rings, but it will not load the rotating palette, change acceleration, max speed, or deceleration, or make him invincible.
 
|-
 
| $FE1A
 
| Flag which is set when the player has a time over.
 
|-
 
| $FE1B
 
| This bitfield tells the game if the player has collected extra lives from rings. Seems to work differently in S3k than in S2.
 
|-
 
| $FE1C
 
| Flag determines if the lives counter needs to be updated
 
|-
 
| $FE1D
 
| Flag determines if the rings counter needs to be updated
 
|-
 
| $FE1E
 
| Flag determines if the timer needs to be updated
 
|-
 
| $FE1F
 
| Flag determines if the score counter needs to be updated
 
|-
 
| $FE20-$FE21
 
| Ring count
 
|-
 
| $FE23
 
| Minutes on clock. Should not go above $09, or the clock will look like shit.
 
|-
 
| $FE24
 
| Seconds. This one shouldn't go above $3B, for the same reason.
 
|-
 
| $FE25
 
| Centiseconds. I don't know what'll happen if this goes out of range, but it's probably not good.
 
|-
 
| $FE26-$FE29
 
| Score (divided by 10)
 
|-
 
| $FE2A
 
| Greatest reference number of passed star poles
 
|-
 
| $FE2B
 
| Starpole ID of the last starpole hit
 
|-
 
| $FE2C
 
| Zone in which the last starpole was hit
 
|-
 
| $FE2D
 
| Act in which the last starpole was hit
 
|-
 
| $FE2E-$FE2F
 
| X position of the last starpole hit
 
|-
 
| $FE30-$FE31
 
| Y position of the last starpole hit
 
|-
 
| $FE32-$FE33
 
| The number of the rings the player had when the last starpole was hit
 
|-
 
| $FE34-$FE37
 
| Copy of the entire clock data when the last starpole was hit
 
|-
 
| $FE35
 
| Minutes on the clock when the last starpole was hit
 
|-
 
| $FE36
 
| Seconds on the clock when the last starpole was hit
 
|-
 
| $FE37
 
| Centiseconds on the clock when the last starpole was hit
 
|-
 
| $FE38-$FE39
 
| Starting art block of the main character when the last starpole was hit
 
|-
 
| $FE3A-$FE3B
 
| Main character's collision layers data when the last starpole was hit
 
|-
 
| $FE3C-$FE3D
 
| Camera's X position when the last starpole was hit
 
|-
 
| $FE3E-$FE3F
 
| Camera's Y position when the last starpole was hit
 
|-
 
| $FE40-$FE41
 
| Water level when the last starpole was hit
 
|-
 
| $FE42
 
| The state of the water movement flag when the last starpole was hit
 
|-
 
| $FE43
 
| The state of the extra lives from rings bitfield when the last starpole was hit
 
|-
 
| $FE44-$FE45
 
| Camera's current maximum Y position when the last starpole was hit
 
|-
 
| $FE46
 
| DSR/DLE routine when the last starpole was hit
 
|-
 
| $FE48
 
| Flag which is set upon special stage entry and cleared when the data saved on special stage entry is restored
 
|-
 
| $FE49
 
| Starpole ID of the last starpole hit before the last special stage entry
 
|-
 
| $FE4A
 
| Zone from which the last special stage was entered
 
|-
 
| $FE4B
 
| Act from which the last special stage was entered
 
|-
 
| $FE50-$FE51
 
| The number of rings the player had when the last special stage was entered
 
|-
 
| $FE52-$FE55
 
| Copy of the entire clock data when the last special stage was entered
 
|-
 
| $FE53
 
| Minutes on the clock when the last special stage was entered
 
|-
 
| $FE54
 
| Seconds on the clock when the last special stage was entered
 
|-
 
| $FE55
 
| Centiseconds on the clock when the last special stage was entered
 
|-
 
| $FE56-$FE57
 
| Starting art block of the main character when the last special stage was entered
 
|-
 
| $FE58-$FE59
 
| Main character's collision layers data when the last special stage was entered
 
|-
 
| $FE5A-$FE5B
 
| Camera's X position when the last special stage was entered
 
|-
 
| $FE5C-$FE5D
 
| Camera's Y position when the last special stage was entered
 
|-
 
| $FE5E-$FE5F
 
| Water level when the last special stage was entered
 
|-
 
| $FE60
 
| The state of the water movement flag when the last special stage was entered
 
|-
 
| $FE61
 
| The state of the extra lives from rings bitfield when the last special stage was entered
 
|-
 
| $FE62-$FE63
 
| Camera's current maximum Y position when the last special stage was entered
 
|-
 
| $FE64
 
| DSR/DLE routine when the last special stage was entered
 
|-
 
| $FE6E-$FEAF
 
| Oscillating numbers data
 
|-
 
| $FEB2
 
| Rings animation counter.
 
|-
 
| $FEB3
 
| Rings animation frame.
 
|-
 
| $FEB6
 
| Spilling rings animation counter.
 
|-
 
| $FEB7
 
| Spilling rings animation frame.
 
|-
 
| $FEC0-$FEC1
 
| Tails's max speed
 
|-
 
| $FEC2-$FEC3
 
| Tails's acceleration
 
|-
 
| $FEC4-$FEC5
 
| Tails's deceleration
 
|-
 
| $FEC6
 
| Tails's lives in 2P mode. Unused in S3K, but its there.
 
|-
 
| $FEC7
 
| This bitfield tells the game if the player has collected extra lives from rings. Used for Tails in 2P mode. Unused in S3K, but its there.
 
|-
 
| $FEC8-$FEC9
 
| Rings collected since level load. Resets if you enter Special/Bonus stage. Starts recounting from 0 when level is reentered. Unknown use.
 
|-
 
| $FF04-$FF05
 
| Perfect counter (leftover from S2). No perfect bonus is given for collecting all the rings, making this variable virtually useless.
 
|-
 
| $FF08-$FF09
 
| Current character (00 - sonic & tails, 01 - sonic, 02 - tails, 03 - knuckles)
 
|-
 
| $FF0A-$FF0B
 
| Character selected in level select (00 - sonic & tails, 01 - sonic, 02 - tails, 03 - knuckles)
 
|-
 
| $FF0E
 
| Number of kosinski compressed data pieces waiting on the KosToRam queue to be decompressed to RAM
 
|-
 
| $FF40-$FF5F?
 
| The KosArt queue, which is a set of arrays of 2 longwords
 
*$00 - the source Kosinski data location
 
*$04 - the destination RAM address
 
|-
 
| $FF60
 
| Number of kosinski art pieces waiting on the queue to be decompressed and DMAed to VRAM (number of modules of the compressed Kosinski art btw)
 
Bit 7 set to 1 indicates that the art has been already decompressed to the Kosinski art buffer ($D000)
 
|-
 
| $FF64
 
| Art location of the moduled kosinski data.
 
|-
 
| $FF96
 
| State of the main character's secondary status bitfield when the last special stage was entered, used to restore any shield the character had when he entered the special stage and cleared once the shield is restored
 
|-
 
| $FFB0
 
| Number of chaos emeralds
 
|-
 
| $FFB1
 
| Number of super emeralds
 
|-
 
| $FFB2-$FFB8
 
| Array of finished special stages. Each byte represents one stage:
 
*0 - special stage not completed
 
*1 - chaos emerald collected
 
*2 - super emerald present but grayed
 
*3 - super emerald present and activated
 
|-
 
| $FFD2-$FFD3
 
| Demo number
 
|-
 
| $FFDA
 
| Debug mode flag
 
|-
 
| $FFE8
 
| 2P versus mode flag
 
|-
 
| $FFEA
 
| 2p mode player 1's character
 
|-
 
| $FFEB
 
| 2p mode player 2's character
 
|}
 
 
===Object Status Table===
 
The starting offset in RAM for this list is $B000. The first object is always player 1; the second is always player 2. Each object is alloted a block of $4A bytes. Note that many of these variables are object-specific - for example, some of them only make sense for Sonic, and some only work on badniks.
 
 
{|border="1"
 
!Offset||Description
 
|-
 
|width="60"|$00-$03||Pointer to object code. Note that this pointer does not necessarily remain constant for a single object.
 
|-
 
|$04||Action flags. The bitfield looks like this:
 
*Bit 0 is the horizontal mirror flag. If set, the object will be flipped on its horizontal axis.
 
*Bit 1 is the vertical mirror flag.
 
*Bit 2 is the coordinate system flag. If clear, the object will be positioned by absolute screen coordinates. This is used for things like the HUD and menu options. If set, the object will be positioned by the playfield coordinates, i.e. where it is in a level. Sonic, Tails and Knuckles use both positioning systems (though I don't know how Tails uses it in a Sonic and Tails game).
 
*Bits 3, 4, 5 and 6 are either unused, or their purpose is unknown.
 
*Bit 7 is the draw object flag. It will be set if the object was onscreen when it came time to draw things. Otherwise, it is clear. There should be no reason to edit this flag, but it's good to know what it does.
 
|-
 
|$05||Routine number. This is always an even value (i.e. it goes in units of 2)
 
|-
 
|$06||Unknown.
 
|-
 
|$07||Width of the object, in pixels.
 
|-
 
|$08-$09||Sprite priority, in units of $80 (00 = front).
 
|-
 
|$0A-$0B||Starting art block. This is an index into an array of cells; to get the actual address, multiply by $20.
 
|-
 
|$0C-$0F||Object's mappings offset.
 
|-
 
|$10-$11
 
|If the object is Sonic, Tails or Knuckles, this is the X playfield coordinate. Otherwise:
 
*If in playfield positioning mode, it is the X playfield coordinate.
 
*If in screen postioning mode, it is the X screen coordinate.
 
|-
 
|$12-$13
 
|If the object is Sonic, Tails or Knuckles, this is the X subpixel playfield coordinate. Otherwise:
 
*If in playfield positioning mode, it is unused.
 
*If in screen positioning mode, it's the Y screen coordinate.
 
|-
 
|$14-$15
 
|If the object is Sonic, Tails or Knuckles, this is the Y playfield coordinate. Otherwise:
 
*If in playfield positioning mode, it is the Y playfield coordinate.
 
*If in screen positioning mode, it is unused.
 
|-
 
|$16-$17
 
|If the object is Sonic, Tails or Knuckles, this is the Y subpixel playfield coordinate. Otherwise:
 
*It's unused.
 
|-
 
|$18-$19||X speed.
 
|-
 
|$1A-$1B||Y speed.
 
|-
 
|$1C-$1D||Potential speed (inertia).
 
|-
 
|$1E||Height/2
 
|-
 
|$1F||Width/2
 
|-
 
|$20||Animation number.
 
|-
 
|$21||Restart animation flag (when $21 is not equal to $20, animation restarts)
 
|-
 
|$22||Current animation frame to display.
 
|-
 
|$23||Current frame in animation script.
 
|-
 
|$24||Animation frame duration (time until next frame).
 
|-
 
|$25||Animation counter.
 
|-
 
|$26||Angle.
 
|-
 
|$27||Second angle (different axis).
 
|-
 
|$28||Collision response bitfield. Tells what the object will do if hit by the character. The bitfield is in the format TTSS SSSS. TT is the type of collision - 00 is enemy, 01 increments the routine counter, 10 is harm, and 11 seems to be a special thing for the starpole. SSSSSS is the size, lifted from a lookup table in the collision response routine.
 
|-
 
|$29||Custom collision property, for special interaction with Sonic. This is used by bosses, badniks, bumpers and other objects. The way in which this byte is used is different for each object. Bosses use this byte as a hit counter.
 
|-
 
|$2A||Status bitfield.
 
Counting from the least significant bit:
 
{|border='1'
 
!Bit||Hex||Description
 
|-
 
|0||$01||X Orientation. Clear is left and set is right.
 
|-
 
|1||$02||Y Orientation. Clear is right-side up, and set is upside-down
 
|-
 
|2||$04||Unknown or unused.
 
|-
 
|3||$08||Set if Sonic is standing on this object.
 
|-
 
|4||$10||Set if Tails is standing on this object.
 
|-
 
|5||$20||Set if Sonic is pushing on this object.
 
|-
 
|6||$40||Set if Tails is pushing on this object.
 
|-
 
|7||$80||Unknown or unused.
 
|} Note that these bits have different meanings for Sonic (see below).
 
|-
 
|$2B
 
|Object shield reaction bitfield.
 
{|border='1'
 
!Bit||Hex||Description
 
|-
 
|3||$08||Bounces off shield.
 
|-
 
|4||$10||Negated by fire shield.
 
|-
 
|5||$20||Negated by lightning shield.
 
|-
 
|6||$40||Negated by bubble shield.
 
|}
 
|-
 
|$2C||Object subtype. For example, the current monitor selected. Has a different meaning for Sonic, Tails and Knuckles.
 
|-
 
|$42-$43||Parent. Address of the object that spawned this one. Has a different meaning for orphans like Sonic, Tails and Knuckles.
 
|-
 
!colspan="2" | Variables specific to Sonic, Tails and/or Knuckles
 
|-
 
!Offset||Description
 
|-
 
|$25
 
|
 
*If Sonic, it's unused.
 
*If Tails, it's the number of flying frames remaining / 2.
 
*If Knuckles, it's something gliding related.
 
|-
 
|$2A||Status bitfield. Counting from the least significant bit:
 
{|border='1'
 
!Bit||Hex||Description
 
|-
 
|0||$01||Orientation. Clear is right and set is left.
 
|-
 
|1||$02||Set if in the air (jump counts).
 
|-
 
|2||$04||Set if jumping or rolling.
 
|-
 
|3||$08||Set if the character isn't on the ground but shouldn't fall. (Usually when he is on a object that should stop him falling, like a platform or a bridge)
 
|-
 
|4||$10||Set if jumping after rolling.
 
|-
 
|5||$20||Set if pushing something.
 
|-
 
|6||$40||Set if underwater.
 
|-
 
|7||$80||Unused.
 
|}
 
You can add the hex values together to use multiple settings at once. Also notice that bits 1 and 2 are used in the character object as a second routine counter.
 
|-
 
|$2B
 
|Secondary status bitfield.
 
{|border='1'
 
!Bit||Hex||Description
 
|-
 
|0||$01||Shield flag. Can be set to create the effect of having a shield, though the graphics will not be loaded.
 
|-
 
|1||$02||Sets invincibility. Behaves like you would expect. No graphics are loaded when set manually.
 
|-
 
|2||$04||Speed Shoes flag. (Doesn't have visible effect in game)
 
|-
 
|3||$08||Unused.
 
|-
 
|4||$10||Fire shield flag.
 
|-
 
|5||$20||Lightning shield flag.
 
|-
 
|6||$40||Bubble shield flag.
 
|-
 
|7||$80||Sets infinite inertia. While the character is in collision with the ground, he will continue moving in the same direction and at the same speed that he was moving before (even if that speed was zero). You can still jump and control him in midair. (A few movement routines are skipped if it's set, which produces this effect).
 
|}
 
|-
 
| $2C
 
|Seconds of air left. Usually $1E; it decrements every second while the player is underwater. Beeps on $18, $13, and $0E. Countdown starts on $0B.
 
|-
 
| $2D
 
|Invert flipping flag.
 
|-
 
| $2E
 
|Object control flag. If bit 7 is not set, the character is under control of another object but can jump out (e.g. being carried by Tails), and if it is, the character is under control of another object and cannot jump out (e.g. LBZ tubes).
 
|-
 
| $2F
 
|Double jump flag. For Sonic:
 
*0 - on ground.
 
*1 - performing an instashield, fire dash, bubble bounce or lightning jump, or has performed the latter three.
 
*2 - has performed an instashield.
 
For Tails:
 
*0 - on ground.
 
*1 - gravity-affected flying.
 
*Above 1 - gravity-less flying.
 
For Knuckles:
 
*0 - on ground.
 
*1 - gliding.
 
*2 - falling after a glide.
 
*3 - sliding across ground.
 
*4 - wall-climbing.
 
*5 - climbing over a wall and onto the ground.
 
|-
 
| $30
 
|Number of flip revolutions remaining.
 
|-
 
| $31
 
|Number of flip revolutions per frame divided by 256.
 
|-
 
| $32-$33
 
|Horizontal control lock. Counts down to 0, left and right control on the ground is locked unless it's 0. Used for springs and bumpers and falling down slopes.
 
|-
 
| $34
 
|Remaining invunerability time. Starts at $78 after Sonic is hit, and seems to decrement every frame until it reaches $00.
 
|-
 
|$35||Remaining time of invincibility. Decremented once every eight frames.
 
|-
 
|$36||Remaining time of Speed Shoes. Decremented once every eight frames.
 
|-
 
|$38||Character ID:
 
*0 - Sonic
 
*1 - Tails
 
*2 - Knuckles
 
|-
 
|$39
 
|Character looking up/ducking counter. Starts off at 0 and is incremented each frame the character is looking up/ducking. When this reaches $78, the camera starts to scroll. Reset to 0 upon release of the up/down button.
 
|-
 
|$3A||Angle on ground in front of sprite.
 
|-
 
|$3B||Angle on ground under sprite.
 
|-
 
| $3C
 
|Stick to convex surfaces flag.
 
|-
 
|$3D||Set if charging a spindash.
 
|-
 
|$3E-$3F
 
|Spindash counter. Cleared when the spindash is started. After each subsequent "rev", $200 is added to the counter, which then rapidly decreases (the algorithm is to logically shift the value right by five bits and subtract the results from the
 
 
original). It maxes out at $800. The game looks at the high-order byte to determine how fast the character should move after the dash is released.
 
|-
 
|$40||Set if jumping.
 
|-
 
|$42-43||RAM address of the last object Sonic stood on.
 
|-
 
|$44||Default height.
 
|-
 
|$45||Default width.
 
|-
 
|$46||Current collision plane/layer, seems to always be $C or $E.
 
|-
 
|$47||Unknown, seems to always be objstatus($46)+1, affects collision.
 
|-
 
!colspan="2" | Variables specific to dynamically reloaded sprites, excluding Sonic, Tails and Knuckles
 
|-
 
|$34||Previous frame.
 
|-
 
|$38-$3B||Pointer to uncompressed art.
 
|-
 
|$3C-3F||Pointer to dPLCs.
 
|-
 
|$40-$41||Address of art in VRAM (the same as starting art block * $20)
 
|}
 
 
{{SCHGuides}}
 
{{SCHGuides}}
 +
[[Category:Sonic Community Hacking Guide]]

Revision as of 09:28, 8 April 2018

SCHG: Sonic the Hedgehog 3 & Knuckles
Main Article
Art Editing
Editing Art
Uncompressed Art
Nemesis Format Art
Kosinski Format Art
Palette Editing
Palette Locations
Pattern Load Requests
Object Editing
Editing Objects
Object Pointers
Object Pointer List #1
Object Pointer List #2
Objects not in either list
Sprite Mappings
Dynamic PLCs
Level Editing
Editing Levels
Object Placement
Ring Placement
Level Layout
16x16 Block Mappings
128x128 Block Mappings
Music Editing
Editing Music
Pointer Format
Header Format
DAC Samples
Universal Voice Bank
Music Pointers (Sonic & Knuckles)
Music Pointers (Sonic 3)
RAM Editing
Editing RAM
Main System Memory Locations
Object Status Table Format
Sonic & Knuckles Collection
Sonic & Knuckles Collection
Music and sound effects

This is the Sonic Community Hacking Guide for Sonic 3 & Knuckles. As Sonic 3 & Knuckles is a "lock-on" game, all offsets below $200000 are in the base Sonic & Knuckles ROM, and all offsets above $200000 are in the connected Sonic the Hedgehog 3 ROM. Since Sonic 3 & Knuckles runs on Sonic & Knuckles' engine, all the information on this page also applies to Sonic & Knuckles alone, with the exception of any pointers above $200000 (which are part of the locked-on Sonic 3 ROM).


Sonic Community Hacking Guide
General
SonED2 Manual | Subroutine Equivalency List
Game-Specific
Sonic the Hedgehog (16-bit) | Sonic the Hedgehog (8-bit) | Sonic CD (prototype 510) | Sonic CD | Sonic CD (PC) | Sonic CD (2011) | Sonic 2 (Simon Wai prototype) | Sonic 2 (16-bit) | Sonic 2 (Master System) | Sonic 3 | Sonic 3 & Knuckles | Chaotix | Sonic Jam | Sonic Jam 6 | Sonic Adventure | Sonic Adventure DX: Director's Cut | Sonic Adventure DX: PC | Sonic Adventure (2010) | Sonic Adventure 2 | Sonic Adventure 2: Battle | Sonic Adventure 2 (PC) | Sonic Heroes | Sonic Riders | Sonic the Hedgehog (2006) | Sonic & Sega All-Stars Racing | Sonic Unleashed (Xbox 360/PS3) | Sonic Colours | Sonic Generations | Sonic Forces
Technical information
Sonic Eraser | Sonic 2 (Nick Arcade prototype) | Sonic CD (prototype; 1992-12-04) | Dr. Robotnik's Mean Bean Machine | Sonic Triple Trouble | Tails Adventures | Sonic Crackers | Sonic 3D: Flickies' Island | Sonic & Knuckles Collection | Sonic R | Sonic Shuffle | Sonic Advance | Sonic Advance 3 | Sonic Battle | Shadow the Hedgehog | Sonic Rush | Sonic Classic Collection | Sonic Free Riders | Sonic Lost World
Legacy Guides
The Nemesis Hacking Guides The Esrael Hacking Guides
ROM: Sonic 1 | Sonic 2 | Sonic 2 Beta | Sonic 3

Savestate: Sonic 1 | Sonic 2 Beta/Final | Sonic 3

Sonic 1 (English / Portuguese) | Sonic 2 Beta (English / Portuguese) | Sonic 2 and Knuckles (English / Portuguese)
Move to Sega Retro
Number Systems (or scrap) | Assembly Hacking Guide | 68000 Instruction Set | 68000 ASM-to-Hex Code Reference | SMPS Music Hacking Guide | Mega Drive technical information