SCHG:Sonic the Hedgehog 3 & Knuckles/RAM Editing

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

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.

RAM offset	Description
$0000-$7FFF	128x128 chunk mappings
$8000-$8FFF	Level layout $8000-$8001 - Number of chunks for each foreground row $8002-$8003 - Number of chunks for each background row $8004-$8005 - Number of foreground rows $8006-$8007 - Number of background rows $8008-$BFFF - List of pointers to each row, interleaved between foreground and background, following the actual chunk data for each row.
$9000-$A7FF	16x16 block mappings
$A800-$A9FF	Background scroll buffer. Used mainly to save data about positions of different layers of parallax backgrounds, but sometimes is used for other purposes in the Screen Events routines.
$AA00-$ABFF	Nemesis decompression buffer
$AC00-$AFFF	Sprite table input. Consists of 8 different priority levels, each level taking up $80 bytes. The first word of each level is the number of objects currently in that priority level multiplied by 2, and the next $3F words are the addresses in RAM (inside the object RAM space) of the objects on that priority level. The information in this table is processed by BuildSprites to create the actual sprite table.
$B000-$CFCB	Object attribute table $B000-$B049 - Reserved object SST for Player 1 in levels, miscellaneous purpose otherwise. $B04A-$B093 - Reserved object SST for Player 2 in levels, miscellaneous purpose otherwise. $B094-$B0DC - Reserved object SST for an object, which clears the number of objects in collision response list ($E380). $B0DE-$CAE1 - Dynamic object SST (Level objects are loaded here). 90 objects total. $CAE2-$CFCB - Reserved object SST (Various important objects, such as Sonic, shields, invincibility stars, and title cards, are loaded here).
$CFCC-$CFDF	Unused
$CFE0-$CFEE	Array of flags used by the HCZ conveyor belts to avoid loading them more than once. The size of the array depends on the highest object subtype used.
$CFEF-$CFFF	Unused
$D000-$DFFF	Kosinski decompression buffer. Used also for software scaling.
$E000-$E37F	Horizontal scroll 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 status table. Only objects in this list are processed by the collision response routine.
$E400-$E4FF	In 1-player mode, this is Sonic's statistic recording buffer, used by Tails' AI. In 2-player mode, this is player 2's position table.
$E422-$E423	Player position X in Special Stage, with each checkerboard field having a size of $100.
$E424-$E425	Player position Y in Special Stage, with each checkerboard field having a size of $100.
$E426-$E427	Player direction in Special Stage.
$E428-$E429	Current player movement speed in Special Stage. Negative if walking backwards.
$E42A	Direction change at the next checkerboard corner in Special Stage. Can be either -4, 0 or 4.
$E42B, $E42C, $E42F, $E430	Unknown in Special Stage.
$E431	This flag is set to 1 while going forward in Special Stage.
$E432, $E433, $E434-$E435, $E436-$E437	Unknown in Special Stage.
$E438-$E439	The number of blue spheres remaining to be collected in a Special Stage.
$E43A-$E43B	The number of rings collected in a Special Stage.
$E43C	Unknown in Special Stage.
$E43D	Special Stage ring collection flags. Bit 0 is set when 50 rings have been collected, bit 1 is set for 100 rings, bit 2 is set for 200 rings, and bit 7 is set when the rings display needs to be refreshed.
$E43E-$E43F	Number of frames remaining till the speed of a Special Stage increases. Initial value is 1800 (i.e. 30 seconds in 60Hz mode) for regular special stages and 2700 (i.e. 45 seconds in 60Hz mode) for Blue Spheres special stages.
$E440	Unknown in Special Stage.
$E442-$E443	Total rings remaining to be collected in a Special Stage. A 50000 points perfect bonus is awarded for collecting all the rings.
$E444-$E445	Special Stage speed. Starts off at $1000 and is incremented by $400 every time the speed increase timer expires until it reaches $2000.
$E436-$E439	Unknown in Special Stage.
$E44A-$E44B	Height of spheres when they fly up after collecting the last blue sphere in Special Stage.
$E44C, $E44D, $E44E-$E44F, $E450	Unknown in Special Stage.
$E500-$E5FF	Position table for player 1
$E600-$E653	Saved competition mode data
$E654-$E65F	Unused
$E660-$E663	Long pointer to the currently-playing save slot's data in memory. Set to $FFFFE6AC when playing save slot 1, $FFFFE6B6 when playing save slot 2, etc.
$E664-$E665	Unused
$E666-$E667	Unknown
$E668-$E6AB	Unused
$E6AC-$E6FF	Variables for each save slot. The format is $A bytes long: Hex Value Description $00-$01 Word Slot State $8000 New Game $0000 Game in Progress $0100 Game Complete $0200 Game Complete with all Chaos Emeralds $0300 Game Complete with all Super Emeralds $02 Byte Current Character $00 Sonic And Tails $10 Sonic $20 Tails $30 Knuckles $03 Byte Current Level $0C Last level for Knuckles $0D Last level for Sonic without Chaos/Super emeralds, or Tails $0E Last level for Sonic with at least all Chaos Emeralds $04-$05 Word Bitmask of Special Stages rings already entered in current zone $06-$07 Word Chaos / Super Emerald collection state. The format is 2 bits per emerald: 0 = not collected, 1 = Chaos Emerald collected, 2 = Chaos Emerald traded for an (inactive) Super Emerald, 3 = Super Emerald collected $08 Byte Current number of lives $09 Byte Current number of continues Note that byte $02 also keeps a record of special stages played through, whether you won or lost it. It updates by $01's.
$E700-$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.
$EB00-$EDFF	Object respawn table. Each object which is part of a level's object placement gets an entry in this table, and whenever the objects manager creates a new object, it sets bit 7 of the object's entry in the object respawn table. While bit 7 is set, the object will not be loaded again by the objects manager. The other seven bits of the entry are free for use by the object - for example, monitors set bit 0 to signify a broken monitor. Since every object which is part of the level's object placement has an entry in this table, the maximum number of objects any level can have in its object placement is 768, although the only level that gets close to that number is AIZ2, with 751 objects.
$EE00-$EE01	Variable set by the horizontal scroll manager to the difference between the old and new camera X positions, multiplied by 256
$EE02-$EE03	Variable set by the vertical scroll manager to the difference between the old and new camera Y positions, multiplied by 256
$EE04-$EE05	Variable set by the horizontal scroll manager to the difference between the old and new camera X positions for player 2, multiplied by 256
$EE06-$EE07	Variable set by the vertical scroll manager to the difference between the old and new camera Y positions for player 2, multiplied by 256
$EE08	Unused, but cleared when the level starts.
$EE09	Unused
$EE0A	Scroll lock for player 1 - if this is set, scrolling routines won't be processed.
$EE0B	Scroll lock for player 2 - if this is set, scrolling routines won't be processed.
$EE0C-$EE0D	Level's target left boundary (Unused)
$EE0E-$EE0F	Level's target right boundary (Unused)
$EE10-$EE11	Level's target upper boundary (Unused)
$EE12-$EE13	Level's target lower boundary.
$EE14-$EE15	Level's left boundary.
$EE16-$EE17	Level's right boundary.
$EE18-$EE19	Level's upper boundary.
$EE1A-$EE1B	Level's lower boundary.
$EE1C-$EE1D	Level's left boundary for player 2.
$EE1E-$EE1F	Level's right boundary for player 2.
$EE20-$EE21	Level's upper boundary for player 2.
$EE22-$EE23	Level's lower boundary for player 2.
$EE24-$EE25	Horizontal scroll delay. If this is nonzero, the upper byte is the offset into the player 1 position table, which is used to calculate camera position. Used for example by the Spin Dash and fire dash.
$EE26-$EE27	Index into Player 1's statistics recording buffer and position table.
$EE28-$EE29	Horizontal scroll delay for player 2.
$EE2A-$EE2B	Index into Player 2's position table.
$EE2C-$EE2D	Screen Y-offset to center the camera to. This is used for looking up or down, which changes the camera Y-offset to show more of the screen.
$EE2E-$EE2F	Screen Y-offset to center the camera to for player 2.
$EE30	Deform lock flag. If this flag is set, camera will not be scrolled and level resize events are not processed.
$EE31	Unused
$EE32	Flag that is set, if camera is going to scroll vertically this frame, because the target bottom boundary was changed. This seems to only be used for the camera scrolling.
$EE33	Routine counter for screen resize routines.
$EE34-$EE38	Unused
$EE39	Fast vertical scrolling flag. If set, screen can be scrolled up to $18 pixels per frame, as opposed to 6 pixels.
$EE3A-$EE3B	Copy of the foreground vertical scroll position for player 2. Seems to be used for the competition mode (Change camera position mid-screen).
$EE3C-$EE3D	Copy of the background vertical scroll position for player 2. Seems to be used for the competition mode (Change camera position mid-screen).
$EE3E-$EE3F	This is the difference between the foreground horizontal position and background horizontal position. Used for various things, such as collision with the background layer.
$EE40-$EE41	This is the difference between the foreground vertical position and background vertical position. Used for various things, such as collision with the background layer.
$EE42-$EE45	Address (in the ROM) of the next ring to the left. Used to more efficiently load unloaded rings when the camera is moved.
$EE46-$EE49	Address (in the ROM) of the next ring to the right. Used to more efficiently load unloaded rings when the camera is moved.
$EE4A-$EE4B	Address (in the ring status table) of the next ring to the left. Used to more efficiently load unloaded rings when the camera is moved.
$EE4C-$EE4D	Unused
$EE4E	Apparent current zone. This is identical to $FE10.
$EE4F	Apparent current act. Unlike $FE11, this is only incremented by the actual end of act score tally, so it differs from $FE11 in levels like AIZ, where $FE11 is set to 1 as soon as the first cutscene is over, while this is incremented only after the end of act points tally.
$EE50-$EE51	Animated palette timer. When set to a negative value, no palette cycling occurs. When set to 0, normal palette cycling occurs. When set to above 0, palette is either faded from black or white, depending on the level.
$EE52-$EE55	Address of the demo playback data.
$EE56-$EE59	Unknown
$EE5A	Unknown, maybe competition mode related.
$EE5B	Unused
$EE5C-$EE5D	Unknown, maybe competition mode related.
$EE5E	Flag used to indicate we started act 3. This flag disables the title cards.
$EE5F	Unused
$EE60-$EE63	Plane A X-position for player 2 in 2p mode.
$EE64-$EE67	Plane A Y-position for player 2 in 2p mode.
$EE68-$EE6B	Copy of plane A X-position for player 2 in 2p mode.
$EE6C-$EE6F	Copy of plane A Y-position for player 2 in 2p mode.
$EE70-$EE71	Unknown
$EE72-$EE73	Unused
$EE74-$EE75	Unused, only referenced in dead code.
$EE76-$EE77	Unused
$EE78-$EE7B	Plane A X-position.
$EE7C-$EE7F	Plane A Y-position.
$EE80-$EE81	Copy of plane A X-position.
$EE82-$EE83	Unused
$EE84-$EE85	Copy of plane A Y-position.
$EE86-$EE87	Unused
$EE88-$EE89	Rounded plane A X-position. The position is rounded down to the last full block ($10 pixels).
$EE8A-$EE8B	Rounded plane A Y-position. The position is rounded down to the last full block ($10 pixels).
$EE8C-$EE8D	Copy of plane B X-position.
$EE8E-$EE8F	Unknown
$EE90-$EE91	Copy of plane B Y-position.
$EE92-$EE93	Unknown, possibly unused
$EE94-$EE95	Rounded plane B X-position. The position is rounded down to the last full block ($10 pixels).
$EE96-$EE97	Rounded plane B Y-position. The position is rounded down to the last full block ($10 pixels).
$EE98-$EE99	Unknown
$EE9A-$EE9B	Unknown, possibly unused
$EE9C-$EE9F, $EEA0-$EEA1, $EEA2, $EEA3	Unknown
$EEA4	Plane double update flag. This is set, when the plane has moved by more than $10 pixels this frame. It is used temporarily to remember to update the next row or column of the plane.
$EEA5	Unused
$EEA6-$EEA7	Special V-int routine. This flag is used to control various special functions that occur during the vertical interrupt. This is mainly used for the LBZ2 ship sequence.
$EEA8-$EEA9	Plane X-wrap value. This flag is used to wrap the horizontal position of the level. It looks like, that this was never used for anything.
$EEAA-$EEAB	Plane Y-wrap value. This flag is used to wrap the vertical position of the level. This is used to create infinitely looping levels.
$EEAC-$EEAD	Plane Y-wrap value masked by $FFF0. Used to wrap the vertical position of the level, while aligning to 16px units.
$EEAE-$EEAF	Layout row mask. Used to wrap vertically while dealing with units of level layout row indices, which are multiples of 4. For example, it's $3C when level wraps every $800 pixels, and $7C when level wraps every $1000 pixels.
$EEB0-$EEB1	Unknown
$EEB2-$EEB3	Special events routine counter.
$EEB4-$EEB5	Various meanings for screen events routines.
$EEB6-$EEB7	Unknown
$EEB8-$EEB9	Unknown
$EEBA-$EEBB	Unused
$EEBC-$EEBD	X-position offset for various objects this frame. Used mainly for looping parts of the level, to make the illusion of constant forward movement.
$EEBE-$EEBF	Unknown
$EEC0-$EEC1	Screen event routine counter. Each routine is 4 units, so this counter can only contain multiples of 4. Affects AIZ2, FBZ2, LBZ2, MHZ2, SOZ2, SSZ1, SSZ2, DEZ2, DDZ, the slot machine bonus stage, the LRZ boss act, the DEZ boss act and the ending sequence.
$EEC2-$EEC3	Trigger event routine counter. Each routine is 4 units, so this counter can only contain multiples of 4. Affects all levels except for the bonus stages, DDZ, and MHZ1. For some reason, the ICZ1 screen event routine also uses this counter, so both the screen and trigger event routines are linked in that act.
$EEC4-$EEC5	Used to trigger various level events or scrolling events. This varies for each level.
$EEC6-$EEC7	Similar to $EEC4, used for different events. Level property (like killer wall in HCZ2 or avalanche in ICZ1). The high byte is set when an Act 1 signpost stops spinning, to signal the code that loads Act 2 into memory. This doesn't happen for AIZ and ICZ since they load Act 2 before the midboss.
$EEC8-$EEC9	Used for drawing the entire plane across multiple frames. It is a counter of sorts, to remember which plane row the draw next.
$EECA-$EECB	Used for drawing the entire plane across multiple frames. This determines how many rows are left to draw.
$EECC-$EECD	Screen shaking flag. If zero, screen is not shaking. If negative, screen is shaking for an earthquake and will continue indefinitely. If positive, screen is shaking from a bomb impact or the like, and the value will be decremented each frame until it reaches zero, then shaking will stop.
$EECE-$EECF	Screen shaking offset: the difference between the "true" camera Y position and what appears on screen that frame. Most acts' screen events add this to $EE84 each frame. AIZ1, HCZ1, CNZ1, FBZ1, ICZ2, MHZ1 and DEZ ignore this value, so you'll need to edit the screen events if you want to add shaking effects in those acts. MHZ2 uses it as an X offset instead of a Y offset (when Robotnik hits the tree) so adds it to $EE80 instead of $EE84. ICZ1 uses it for both, depending on where in the level you are.
$EED0-$EED1	Stores the value that $EECE had during the previous frame.
$EED2-$EED3	Secondary screen event routine counter, used by some acts.
$EED4-$EED5	Various meanings in level events, used for example as the X-position for destroying blocks in the CNZ miniboss.
$EED6-$EED7	Various meanings in level events, used for example as the Y-position for destroying blocks in the CNZ miniboss.
$EED8-$EEEB	Various meanings in level events and sometimes other game modes. Every word usually has different meaning.
$EEEA-$EF0D	FBZ2 cloud object pointers.
$EEEA-$EF39	V-Scroll buffer. The buffer contains 20 entries, where an entry is a word for foreground vertical position, and a word for background vertical position. Each 16 pixel column of the screen can be scrolled a different amount as per contents of this buffer. This effect is used only in rare occasions (examples are: MGZ2 level collapse when boss fight starts, LBZ1 building breakdown before boss).
$EEEA	Various other uses which are unknown
$EF3A-$EF3B	Is set to indicate that there are object(s) that are meant to mask other sprites horizontally. These sprites are set to x-position 0, which makes VDP mask overlapping sprites. various level events use this to hide some artifacts.
$EF3C-$EF3D	If set, an alternate address is used for the sprite attribute table data.
$EF3E-$EF3F	Flag that if set, changes the state of $EF3C
$EF40-$EF43	Unknown, seems to have various functions.
$EF44-$EF47	Unknown
$EF48	Competition menu item (00 = Grandprix, 01 = Matchrace, 02 = Timeattack, 03 = Exit)
$EF49	Flag which determines whether the second player in a 2P versus game is player-controlled or just a "ghost" of the first player.
$EF4A	Competition menu zone. This is different from the actual zone id, which is later calculated based on this flag.
$EF4B	Data select save selection. This also includes NO SAVE and DELETE options.
$EF4C-$EF4D	Stores the data select player mode for NO SAVE option (00 = Sonic & Tails, 01 = Sonic, 02 = Tails, 03 = Knuckles) (see also $FF08)
$EF4E	Competition menu monitor selection. If set, monitors are disabled.
$EF4F	Unused
$EF50	Keeps track of whether controller 1 has pressed the start button. It is not clear why this is necessary.
$EF51	Unused
$EF52-$EF55	Unknown
$EF56-$EF57	Flag that if set, SRAM save and load routines will disable interrupts while SRAM is enabled. This is likely done to avoid interrupts firing while SRAM is enabled, that could crash the processor.
$EF58-$EF59	Unused
$EF5A-$EF5D	There are 2 object lists; Sonic 3 list, and Sonic & Knuckles list. This flag points to either one depending on the level ID.
$EF5E-$EF5F	Used to temporarily store ring count, while transitioning to act 3.
$EF60-$EF63	Used to temporarily store level timer value, while transitioning to act 3.
$EF64-$EF65	Position Y of the window of active objects. Only actually used in glowing spheres bonus stage. Objects with Y coordinate lower or at least $280 higher than that will despawn.
$EF66-$EF67	Alternate screen shaking flag, only used when Hyper Knuckles hits a wall after gliding. If zero, screen is not shaking. If nonzero, the value will be decremented each frame until it reaches zero, then shaking will stop.
$EF68-$EF69	Unknown, always set to $98, and only ever used to set the art tile of various Special Stage Result objects.
$EF6A-$EF6B	Zone and act is stored here during Special Stage Results screen.
$EF6C-$EF6D	Flag which is set to $FF00 when a Super Emerald special stage is newly completed. This stops the HPZS initalizer from repeating the "beam" effect that you see when you go to HPZ from a giant ring to pick the special stage in the first place.
$EF6E	Seems to be a copy of $FE16
$EF6F	Unused
$EF70	Seems to be a copy of $FE16, specifically used for HPZS
$EF71	Unused
$EF72-$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.
$EF74-$EF77	Address of secondary plane buffer. If set to 0, it is ignored.
$EF78	The number of frames to hold buttons specified by $EF79 in S&K demos.
$EF79	The buttons to hold in S&K demos.
$EF7A-$EF7B	Currently running demo ID.
$EF7C-$EF7F	Unused
$EF80-$EF81	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	Target underwater palette. Used to fade the underwater palette slowly.
$F080-$F0FF	Current underwater palette.
$F100-$F57F	Plane buffer. During the normal level processing period, display update routines decide which tiles need to be updated and write the results here, and then in V-int a routine processes this and updates the planes accordingly. The first word of each entry in this buffer is the address in VRAM to write to - if this is 0, the buffer processing routine terminates. The second word is the number of 16x16 tiles to be written - 1, and the sign bit of this word being set indicates that the constituent 8x8 tiles are to be written column-by-column rather than row-by-row. Following this is the actual data to write. Warning: Some levels can, on some occasions, overflow from this buffer, inevitably causing a crash! This can be fixed by carefully rearranging RAM.
$F580-$F5FF	VRAM buffer. Used to temporarily hold data while it is being transferred from one VRAM location to another.
$F600	Game mode flag. This flag is used to determine what game mode to go to next. This only takes effect when the last game mode ends (some game modes check for this flag specifically). 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... Known meanings of certain values of the lower 7 bits: $00 - Game initialization or restart e.g. after Game Over $04 - Show SEGA logo, which leads to the title screen $08 - Load a level, and start the demo there $0C - Load a level $10 - Reset game mode to $00 $14 - Go to the continue screen $18 - Reset game mode to $00 $1C - Go to level select $20 - Does nothing. $24 - Go to level select $28 - Go to level select $2C - Go to blue spheres challenge screen $30 - Show blue spheres challenge results screen $34 - Go to special stage $38 - Go to competition mode menu $3C - Go to competition mode player select menu $40 - Go to competition mode level select menu $44 - Go to competition mode results screen $48 - Show special stage results $4C - Go to data select screen $50 - Go to time attack records screen
$F601	Unused
$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 cutscene 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.
$F608-$F60D	Unused
$F60E-$F60F	VDP command for mode register 2
$F610-$F613	Unused
$F614-$F615	Demo time left & Time until demo starts from title screen.
$F616-$F617	Foreground vertical scroll position.
$F618-$F619	Background vertical scroll position.
$F61A-$F61D	Unused, but cleared in various places.
$F61E-$F61F	Foreground vertical scroll position for player 2.
$F620-$F621	Background vertical scroll position for player 2.
$F622	Teleport timer (leftover from Sonic 2).
$F623	Teleport active flag (leftover from Sonic 2).
$F624-$F625	VDP register $A (H-INT counter) cache.
$F626	Number of bytes from the palette start to be ignored in screen fading routines.
$F627	Number of palette entries minus one to be affected in screen fading routines. The first affected palette entry index is half of the value in $F626.
$F628-$F629	Number of lag frames per level loop. Displayed in the place of the minutes counter in the debug HUD.
$F62A	V-INT routine ID.
$F62B	Unused
$F62C	Number of sprites rendered on screen.
$F62D	Unused
$F62E-$F631	Address to a list of offsets, used in various horizontal interrupt routines, to load the water palette gradually. These are offsets are offsets to either water palette, or the normal palette, and target CRAM locations. 3 colors are loaded each scanline, and for each scanline, new offset is read.
$F632-$F635	Counters used for palette cycling.
$F636-$F639	Random number generator seed & result.
$F63A-$F63B	Game paused flag.
$F63C-$F63F	Unused
$F640-$F641	Used to hold the low word of a DMA transfer command, which is then sent to the VDP control port, to get around a hardware bug.
$F642-$F643	Unused
$F644-$F645	H-int enable flag. This flag is used to make sure the horizontal interrupt code is never run twice in a single frame unintentionally. If set, the next H-int will be enabled.
$F646-$F647	Same as $F648.
$F648-$F649	Current water level. Should be a valid Y-axis value. Remember, the top of the level is $0000.
$F64A-$F64B	Target water level. If this differs from $F648, the water level will move up or down $F64C lines per frame until they match.
$F64C	The rate at which water rises or falls during a change in water level.
$F64D	Incremented each time a player enters water.
$F64E	Set to 1 if water covers the entire visible screen; clear otherwise.
$F64F	If set, H-int routines will also update the HUD numbers, process the Nemesis queue, and update the demo timer flag.
$F650, $F652-$F65B	Counters used for palette cycling.
$F651	Seems unused
$F65C-$F65D	Offset into the Super/Hyper color array, determines which set of colors we are currently on. Each palette entry is 2 bytes and there are 3 entries per set, so this is always a multiple of 6.
$F65E	Number of frames remaining until the next set of Super/Hyper colors are loaded into the palette.
$F65F	The current state of Super/Hyper palette rotation. 0 means disabled, 1 means the character is newly transforming to Super/Hyper, -1 ($FF) means the player is fully transformed, 2 means the character was Super/Hyper and is transforming back to normal.
$F660-$F661	Timer used in the outro to briefly wait before starting the credits.
$F662-$F663	Unused, but cleared.
$F664	Dual collision plane flag. Set to -1 ($FF) when there are two collision planes active (Examples: HCZ2 wall chase, MGZ2 partial level collapse, SOZ2 rising sand).
$F665	When set to -1 ($FF), hitting the lower level border won't lead to death.
$F666	Hyper Sonic Dash screen flash timer. Usually zero, except while the screen flash is visible. Starts at 4 and decreases by one each frame.
$F667	Tails super flag, same as $FE19, just for Tails.
$F668	Same as $F65C, but for Tails. So this variable is used to control Tails' colors, and $F65C is used to control the Super Sonic flickies.
$F669	Same as $F65E, but for Tails. So this variable is used to control Tails' colors, and $F65E is used to control the Super Sonic flickies.
$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.
$F66C	Counter used by Super Flickies to determine which entry from collsion response list to check next as a possible target.
$F66D-$F66F	Unused
$F670-$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.
$F672-$F675	Unused
$F676	Follow custom position flag. If this flag is set, this frame player 1's position is substituted for custom positions. This is used to focus scrolling on certain objects in the game.
$F677	Unused
$F678-$F679	Follow custom position X-position.
$F67A-$F67B	Unused
$F67C-$F67D	Follow custom position Y-position. Must come 4 bytes after the X-position.
$F67E-$F67F	Unused
$F680-$F6DF	Pattern load queue. Each entry in this consists of one longword followed by one word, the longword being the location in ROM of the compressed art, and the word being the VRAM location to decompress to. Can store a maximum of 16 entries, but a coding error in the clearing routine means that storing a PLC in the last slot screws everything up, so effectively only 15 requests can be stored at one time.
$F6E0-$F6E3	The address in ROM of the decompression routine to be used for the art
$F6E4-$F6F7	Used by the PLC routines using decompression. No idea what their function is, although it seems they get passed in as parameters to the decompression routine, and are stored updated when the routine returns.
$F6F8-$F6F9	The total number of tiles left to be decompressed for the current piece of art
$F6FA-$F6FB	The number of tiles left to be decompressed in the current frame
$F6FD-$F6FF	Unused
$F700-$F701	Unknown
$F702-$F703	Tails control counter. Counts how long until the CPU takes control.
$F704-$F705	Tails respawn counter.
$F706-$F707	Unused
$F708-$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.
$F712-$F72D	Unknown, seems to be unused however.
$F72E	Flag used to determine which animated palette AIZ1 uses.
$F72F	Unused
$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.
$F731-$F73D	Unused
$F73E	Tails carrying flag. Set to 1 whenever Tails carries Sonic.
$F73F	Number of frames until Tails can catch Sonic again. Used to avoid immediate catching after Sonic jumps off.
$F740-$F741	Unknown, something to do with the software scaler used by MGZ2 boss and SSZ badniks.
$F742-$F743	Unused
$F744-$F745	Unknown
$F746	Unknown
$F747	Unused
$F748	Same as $F604, but for the title screen.
$F749	Same as $F605, but for the title screen.
$F74A, $F74B, $F74C-$F74D, $F74E	Unknown
$F74F	Flag that disables Knuckles' wall grab when set to a negative value.
$F750-$F75F	Unused
$F760-$F761	Sonic's and Knuckles' top speed
$F762-$F763	Sonic's and Knuckles' acceleration
$F764-$F765	Sonic's and Knuckles' deceleration
$F766	Sonic's and Knuckles' current mapping frame number.
$F767	Unused
$F768	Angle value at Sonic's left sensor
$F769	Unused
$F76A	Angle value at Sonic's right sensor
$F76B	Unused
$F76C-$F76D	Routine counter for object spawning.
$F76E-$F76F	Camera X position rounded down to last multiple of $80. Used in the object spawning routine.
$F770-$F771	Camera Y position rounded down to last multiple of $80. Used in the object spawning routine.
$F772-$F775	Long pointer to level object list address of next object to spawn when moving right.
$F776-$F779	Long pointer to level object list of next object to spawn when moving left.
$F77A-$F77B	Pointer into the object respawn table in RAM. Points to the entry associated with the next object to spawn when moving left.
$F77C-$F77D	Pointer into the object respawn table in RAM. Points to the entry associated with the next object to spawn when moving right.
$F77E-$F793	Unused
$F794-$F795	Some type of timer used in palette fade routines.
$F796-$F799	Pointer to the currently used collision layer for players. Is always the same as either $F7B4 or $F7B8.
$F79A-$F7A9	Unused
$F7AA	Boss flag. Set when a boss is active, and cleared after defeat or end of sequence.
$F7AB-$F7AF	Unused
$F7B0-$F7B3	Unknown, used by some objects for storing player-specific state.
$F7B4-$F7B7	Pointer to collision layer 1 of this level.
$F7B8-$F7BB	Pointer to collision layer 2 of this level.
$F7BC-$F7BF	Unused
$F7C0	MHZ pollen and leaves counter. This count how many pollen or leaves are active, and will stop spawning more if 10 or more pollen/leaves are active.
$F7C1	Unknown flag used in MHZ.
$F7C2	Unknown
$F7C3	Unknown
$F7C4-$F7C5	Unknown
$F7C6	Reverse gravity flag. Only in Sonic & Knuckles.
$F7C7	Unknown
$F7C8	Wind tunnel flag. Set if player 1 is in a wind tunnel.
$F7C9	Wind tunnel flag. Set if player 2 is in a wind tunnel.
$F7CA	Controller lock for controller 1.
$F7CB	Controller lock for controller 2.
$F7CC-$F7CF	Unused
$F7D0-$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.
$F7D6-$F7D9	Unused
$F7DA-$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.
$F7DC-$F7DD	Unused, referenced in dead code.
$F7DE	Tails' current mapping frame number.
$F7DF	Tails' tails current mapping frame number.
$F7E0-$F7EF	Level trigger array. This has different meanings in most levels, but generally it is used to determine if a switch has been pressed, and platforms or other objects may react to these button presses using this array.
$F7F0-$F7FF	Level animation counter. Each word is a different counter, and these are used to process animated level art.
$F800-$FA7F	Sprite table buffer. This is a temporary buffer used to store VDP sprite data, and it is DMA'd to VRAM each frame.
$FA80-$FA81	Unused, but cleared.
$FA82-$FA83, $FA84-$FA85, $FA86-$FA87, $FA88	Unknown
$FA89	Flag that if set, will tell Mecha Sonic's head to get deleted.
$FA8A-$FA8B	Unknown
$FA8C-$FA8D	Unused, but written to once.
$FA8E-$FA8F, $FA90-$FA91, $FA92-$FA93, $FA94-$FA95, $FA96-$FA97, $FA98-$FA99, $FA9A-$FAA1, $FAA2, $FAA3, $FAA4-$FAA5	Unknown
$FAA6-$FAA7	Pointer to a signpost object. Hidden Monitors use this to easily find the currently active signpost used for bouncing.
$FAA8	End-of-level flag. Set when a mid-boss or end boss is defeated, set back to zero when the results screen goes away.
$FAA9	Unknown flag which is something to do with control lock
$FAAA	Flag which is set when a title card goes away, or when an Act 1 results screen goes away.
$FAAB	Unknown flag which is only used by the LBZ1 boss.
$FAAC, $FAAD, $FAAE-$FAAF, $FAB0-$FAB1, $FAB2-$FAB3, $FAB4-$FAB5, $FAB6-$FAB7, $FAB8, $FAB9, $FABA-$FABB, $FABC-$FABD	Unknown
$FABE	Unused, but written to once.
$FABF	Flag that if set, palette rotation scripts will not be processed.
$FAC0, $FAC1, $FAC2-$FAC3	Unknown
$FAC4-$FAC7	Unused
$FAC8-$FACB, $FACC, $FACD, $FACE-$FACF	Unknown
$FAD0-$FAD9	Unused
$FADA-$FADD	Unknown
$FADE-$FAED	Data used by palette rotation scripts.
$FAEE-$FAEF	Unused, however should not be written to; Needs to be 0 for palette rotation script routine.
$FAF0-$FAF1	Unknown
$FAF2-$FAF3	Unused
$FAF4-$FAF5	Unknown
$FAF6-$FAF7	Unused
$FAF8-$FAF9, $FAFA-$FAFB, $FAFC-$FAFD	Unknown
$FAFE-$FAFF	Unused
$FB00-$FBFB	VDP command buffer. Stores up to 18 sets of queued up VDP commands to be issued later.
$FBFC-$FBFF	VDP command buffer free slot. Stores the address of the first available empty place in the VDP command buffer.
$FC00-$FC7F	Normal dry palette.
$FC80-$FCFF	Target dry palette. Used to fade the underwater palette slowly.
$FD00-$FDFF	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.
$FE00-$FE01	Unused
$FE02-$FE03	Level restart flag.
$FE04-$FE05	Level frame timer.
$FE06	Object currently selected in debug mode.
$FE08	Object placement mode routine counter.
$FE09	Object placement mode flag (0 - normal, 1 - object placement, 2 - frame cycling)
$FE0A	Delay countdown until camera movement starts in object placement mode.
$FE0B	Current camera movement speed in object placement mode.
$FE0C-$FE0F	Counts the number of times V-int has run.
$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
$FE13-$FE17	Unused
$FE18	Number of continues.
$FE19	Super/Hyper Sonic flag. 1 means Super and -1 ($FF) means Hyper. Setting this will load the Super/Hyper 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	Number of rings collected.
$FE22-$FE23	Minutes counter for the level timer.
$FE24	Seconds counter for the level timer.
$FE25	Frame counter for the level timer.
$FE26-$FE29	Score (divided by 10)
$FE2A	ID of the last starpole the player has hit.
$FE2B-$FE47	Starpole variables. When you hit a starpole, these variables are stored from the current actual values. When you die, the values are loaded from here. $FE2B - ID of the last starpole the player has hit. $FE2C - Current zone. $FE2D - Current act. $FE2E-$FE2F - X-position of the starpole. $FE30-$FE31 - Y-position of the starpole. $FE32-$FE33 - Number of rings collected. $FE34-$FE35 - Minutes counter for the level timer. $FE36 - Seconds counter for the level timer. $FE37 - Frames counter for the level timer. $FE38-$FE39 - VDP pattern index for player 1. $FE3A-$FE3B - Top and LRB collision bit for player 1. $FE3C-$FE3D - Plane A X-position. $FE3E-$FE3F - Plane A Y-position. $FE40-$FE41 - Water Y-position. $FE42 - Water fullscreen flag. $FE43 - Extra lives from rings bits. $FE44-$FE45 - Level's bottom boundary. $FE46 - Screen resize routine counter. $FE47 - Player 1's shield state.
$FE48	Flag that determines which of the two sets of variables to restore. 0 is for starpole, anything else is for the special stage one.
$FE49-$FE65	Special stage variables. When you enter a special stage, these variables are stored from the current actual values. When you return, the values are loaded from here. $FE49 - ID of the last starpole the player has hit. $FE4A - Current zone. $FE4B - Current act. $FE4C-$FE4D - X-position of the starpole. $FE4E-$FE4F - Y-position of the starpole. $FE50-$FE51 - Number of rings collected. $FE52-$FE53 - Minutes counter for the level timer. $FE54 - Seconds counter for the level timer. $FE55 - Frames counter for the level timer. $FE56-$FE57 - VDP pattern index for player 1. $FE58-$FE59 - Top and LRB collision bit for player 1. $FE5A-$FE5B - Plane A X-position. $FE5C-$FE5D - Plane A Y-position. $FE5E-$FE5F - Water Y-position. $FE60 - Water fullscreen flag. $FE61 - Extra lives from rings bits. $FE62-$FE63 - Level's bottom boundary. $FE64 - Screen resize routine counter. $FE65 - Player 1's shield state.
$FE65	Routine counter for LRZ special rocks.
$FE66-$FE69	Address of leftmost LRZ rock, used for loading.
$FE6A-$FE6D	Address of rightmost LRZ rock, used for loading.
$FE6E-$FEAF	Oscillating numbers data.
$FEB0	Unknown
$FEB1	Unknown
$FEB2	Rings animation counter.
$FEB3	Rings animation frame.
$FEB4	Unknown
$FEB5	Unknown
$FEB6	Lost rings animation counter.
$FEB7	Lost rings animation frame.
$FEB8-$FEB9	Lost rings animation accumulator(?)
$FEBA-$FEBB	Unknown
$FEBC-$FEBD	Unused
$FEBE	Unused, but referenced in some code.
$FEBF	Extra lives bits from rings for player 2.
$FEC0-$FEC1	Tails' max speed
$FEC2-$FEC3	Tails' acceleration
$FEC4-$FEC5	Tails' deceleration
$FEC6	Tails' lives in 2P mode. Unused in S3K, but referenced in code.
$FEC7	Unknown
$FEC8-$FEC9	Rings collected since level load. Resets if you enter Special/Bonus stage. Starts recounting from 0 when level is reentered. Not sure what this is used for.
$FECA-$FECB	Same as $FEC8, but for player 2.
$FECC-$FECD	Strange counter, that is incremented when a monitor or a ring gives you an extra life, and also when a robotnik monitor has been destroyed.
$FECE-$FECF	Strange counter, that is incremented when a robotnik monitor has been destroyed by player 2. Oddly, this counter does not get incremented for extra lives; Instead, $FECC is despite being player 2.
$FED0-$FED1	Number of rings counter for player 2. It is unclear if this is ever used for anything.
$FED2-$FED5	Unknown, seems to be unused.
$FED6-$FED9	Unknown, seems to be level timer for player 2, unknown if this is used in any way.
$FEDA	Unknown
$FEDB	Unused
$FEDC-$FEDD	Unknown
$FEDE-$FEDF	Unused, but cleared once.
$FEE0-$FF01	Unused
$FF02-$FF03	Unused, but cleared once.
$FF04-$FF05	Total rings remaining to be collected in a level. No perfect bonus is actually given for collecting all the rings, making this variable virtually useless.
$FF06-$FF07	Unused, but cleared once.
$FF08-$FF09	Player mode (00 = Sonic & Tails, 01 = Sonic, 02 = Tails, 03 = Knuckles, 04 = Blue Knuckles) (see also $EF4C)
$FF0A-$FF0B	Character selected in level select (00 = Sonic & Tails, 01 = Sonic, 02 = Tails, 03 = Knuckles, 04 = Blue Knuckles)
$FF0C-$FF0D	Unused, but cleared once.
$FF0E-$FF0F	Number of Kosinski compressed data pieces on the Kosinski decompression queue ($FF40-$FF5F) waiting to be decompressed to RAM. The most significant bit of this being set signifies a decompression is in progress.
$FF10-$FF37	Kosinski queue processing routine register backup. Registers d0-d6 and a0-a2 are backed up here in case the Kosinski queue processing routine is interrupted by V-Int. They're restored the next time the processing routine is called.
$FF38-$FF39	Kosinski queue processing routine status register backup. In case the processing routine is interrupted by V-Int, the SR is stored here and restored the next time the routine is called.
$FF3A-$FF3D	Kosinski queue processing routine program counter backup. In the instance of the processing routine being interrupted by V-Int, when V-Int is ready to return, the processing does not resume. Instead, by means of the subroutine at $1BF0, program resumption is forced to occur at $1D0C, and the actual overwritten program counter value gets stored here. Next time the processing routine is called, the routine at $1CFC kicks in, pushing this value and the stored SR onto the stack and executing an RTE, causing both to get restored and the processing to resume.
$FF3E-$FF3F	The Kosinski queue processing routine uses this to store words byte-swapped. It's used by the processing routine the same way the stack is used by the normal Kosinski decompression routine.
$FF40-$FF5F	The Kosinski decompression queue. Each entry consists of two longwords: $00 - the source Kosinski data location $04 - the destination RAM address to decompress to Since this is 32 bytes long, only 4 pieces can be stored on it at one time.
$FF60-$FF61	Number of modules left to decompress in the current Kosinski Moduled archive. Bit 7 indicates that the current module has finished decompressing and can be DMA'd to VRAM.
$FF62-$FF63	The decompressed size of the last module of the KosinskiM data divided by 2. All other modules have a fixed decompressed size of $1000.
$FF64-$FF7B	The KosinskiM decompression and DMA queue. Each entry consists of a longword followed by a word: $00 - the source Kosinski module location $04 - the destination VRAM address to DMA the decompressed module to Like the decompression queue, this can also only store 4 pieces at a time.
$FF7C-$FF7D	Copy of controller 2, something to do with competition mode demos.
$FF7E-$FF7F	Unknown
$FF80-$FF81	Unknown, used in the level select.
$FF82-$FF83	Selected item in level select.
$FF84-$FF85	Selected sound in sound test.
$FF86	Option number in title screen.
$FF87-$FF89	Unused
$FF8A	Competition mode monitor selection. If set, monitors are disabled.
$FF8B	Competition mode type (0 = grand prix, 1 = match race, -1 = time attack).
$FF8C-$FF8D	Unused
$FF8E-$FF8F	Total amount of bonus added this frame.
$FF90-$FF91	Used to store what music to resume after other music like the drowning music.
$FF92-$FF95	Special Stage entry rings entered for this level. Each bit is a single entry ring, when that bit is set, the entry ring will not appear again.
$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.
$FF97	If set, the sprite and ring loaders will not clear the respawn table when the level loads. Used for returning from special and bonus stages.
$FF98-$FF99	Unused
$FF9A	Apparent Zone in which the last starpole was hit (See $EE4E)
$FF9B	Apparent Act in which the last starpole was hit (See $EE4B)
$FF9C	Apparent Zone in which special stage or bonus stage was entered (See $EE4E)
$FF9D	Apparent Act in which special stage or bonus stage was entered (See $EE4B)
$FF9E	Unused
$FF9F	Blue Spheres challenge uses this to determine whether the header was "SEGA MEGA DRIVE" (1) or "SEGA GENESIS" (0)
$FFA0	Set to 1 if the full Blue Sphere mode is available because Sonic & Knuckles is locked-on to Sonic 1; it's 0 for any other game
$FFA1	Unknown, something to do with blue spheres challenge.
$FFA2-$FFA5	Map section IDs in Blue Sphere
$FFA6-$FFA9	Level number in Blue Sphere
$FFAA, $FFAB, $FFAC, $FFAD	Unknown
$FFAE-$FFAF	0 if locked on to Sonic 3; nonzero otherwise.
$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
$FFB9	Unused
$FFBA	Flag that when set, prevents Sonic and Knuckles from transforming into super or hyper.
$FFBB	If this is set to 0, Sonic 3 special stages will run. If it's 1, Sonic & Knuckles special stages will run.
$FFBC	Title screen animation flag. Sonic 3 title screen uses the fullscreen Sonic animation to transition from SEGA to title screen. It uses 2 Plane A and Plane B nametables and switches between them after they have been updated. This flag keeps track of which one to transition to next.
$FFBD	Delay timer before the next animation transition.
$FFBE-$FFBF	Animation frame number for the title animation.
$FFC0-$FFC3	Amount of score required for the next extra life.
$FFC4-$FFC7	Amount of score required for the next extra life for player 2.
$FFC8-$FFC9	Unused
$FFCA-$FFCD	Player 1's mappings address is stored here while in debug mode.
$FFCE-$FFCF	Player 1's VDP pattern index is stored here while in debug mode.
$FFD0-$FFD1	Demo mode flag. Set when demo mode is active.
$FFD2-$FFD3	Demo number.
$FFD4	Blue Sphere flag. This is 1 in the standalone Blue Spheres game, and 0 in regular special stages.
$FFD5	Unused
$FFD6-$FFD7	Number of cycles between two V-ints. The purpose of this flag is not known, as the hardware always has specific processor speeds in 50hz and 60hz versions, so you could use the hardware version register to get the region.
$FFD8	Hardware register value, specifically the region bits (bits 6 and 7). Bit 7 - If clear, it is a domestic model (Japan/Asia), else it is an overseas model. Bit 6 - If clear, it is a NTSC (60hz) system, else it is a PAL (50hz) system.
$FFD9	Unused
$FFDA-$FFDB	Debug mode flag.
$FFDC-$FFDF	Unused
$FFE0	Level select cheat flag.
$FFE1	Slow motion cheat flag.
$FFE2-$FFE3	Debug mode cheat flag. If this flag is set, holding A while entering level enables debug mode.
$FFE4-$FFE5	Unused, but cleared and referenced in dead code.
$FFE6-$FFE7	Unused, but cleared and referenced in dead code.
$FFE8-$FFE9	2P versus mode flag.
$FFEA	2p mode player 1's character.
$FFEB	2p mode player 2's character.
$FFEC-$FFEF	Unused
$FFF0-$FFF1	Must be $4EF9 (68k opcode for long jump) as this address is the vertical interrupt vector.
$FFF2-$FFF5	Pointer to the current vertical interrupt routine.
$FFF6-$FFF7	Must be $4EF9 (68k opcode for long jump) as this address is the horizontal interrupt vector.
$FFF8-$FFFB	Pointer to the current horizontal interrupt routine.
$FFFC-$FFFF	Contains the ASCII string "SM&K" to indicate that the checksum is correct.

Object Status Table format

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 allocated 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.

Offset	Description
$00-$03	Pointer to object code. Note that this pointer does not necessarily remain constant for a single object.
$04	Render 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. Bits 3 and 4 are either unused, or their purpose is unknown. Bit 5 is the static mappings flag. If set, this indicates that the mappings pointer for this object points directly to the pieces data for this frame, and implies that the object consists of only one sprite piece. Bit 6 is the compound sprites flag. If set, this indicates that the current object's status table also contains information about other child sprites which need to be drawn using the current object's mappings: Word $16 of the status table indicates the number of child sprites. Following this word is the actual data for each sprite. The format is six bytes per sprite: the first word is the base X position, the next word is the base Y position, the next byte is ignored and the last byte is the mapping frame to display. Bit 7 is the on-screen flag. It will be set if the object is on-screen, and clear otherwise.
$05	Routine number. This is always an even value (i.e. it goes in units of 2)
$06	Height of the object, in pixels.
$07	Width of the object, in pixels.
$08-$09	Sprite priority, in units of $80 (00 = front).
$0A-$0B	The lower 11 bits of this represent the starting art block. This is an index into an array of cells; to get the actual address, multiply by $20. Bits 14 and 13 are used to specify the default palette line the sprite uses, and bit 15 is the priority flag - if this is set, the sprite will be given high priority.
$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, it's unused.
$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 the Y screen coordinate.
$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. $00 represents flat ground. $80 is the ceiling, $40 is a wall to the left of the object, $C0 is a wall to the right of the object. $20 is a 45 degree slope going down to the right, $E0 is a 45 degree slope going up to the right, and so on.
$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: 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 RSS flag, set if the object should remember that it is destroyed. See offsets $3B and $3C below. 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 Set if this object is about to be deleted. Note that these bits have different meanings for Sonic (see below).
$2B	Object shield reaction bitfield. 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.
$2E-2F	Used as a timer/counter, upon completion the routine will jump to a pointer in $34.
$34-$37	Stores a code pointer branched to from various routines upon meeting certain conditions.
$3B	If the RSS flag is set, this is the bit (0-7) to be cleared when the object is destroyed. See bit 2 of offset $2A above.
$3C-$3D	If the RSS flag is set, this is the RAM address to be modified when the object is destroyed. See bit 2 of offset $2A above.
$46-$47	Used by child objects to point to their parent.
$48-$49	RAM location of the object's entry in the object respawn table.
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: 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. 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 invulnerability time. Starts at $78 after Sonic is hit, and is decremented 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.
$37	Some sort of bitfield. If bit 7 of this is set, whenever the player is hit, even if he does not have a shield the game will act like he does and he will just recoil instead of losing rings. If he actually has a shield, however, he will lose it, as the shield check takes precedence over this bit check. Used, for example, by the spinning tops in MGZ.
$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 Spin Dash.
$3E-$3F	Spin Dash counter. Cleared when the Spin Dash 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	The bit in the 16x16 entries in the 128x128 block mappings to check for top solidity. Is either $C (for the default collision layer), or $E (for the alternate collision layer).
$47	The bit in the 16x16 entries in the 128x128 block mappings to check for left/right/bottom solidity. Is either $D (for the default collision layer), or $F (for the alternate collision layer).
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)