The Pit — Work RAM

Work RAM lives at `0x8000`–`0x87FF`. Each name below describes the cell by its role in the running game; the hex address is the stable identity. Cells that share a byte, or whose role is only partly pinned, carry a terse caveat.

Address	Name	Description
8000	creditCount	Credit counter; banked from the coin lines (clamp 9), spent on start; the corruption-watchdog anchor
8001	gameState	0 attract / 1 one-player / 2 two-player / 3 credit-standby / 4 attract-demo
8002	activePlayer	Active player index (1 or 2); read on the P1/P2 handoff
8003	coinSwAccum	Coin switch (IN1 bit0) edge-detect accumulator; a completed pulse banks a credit
8004	start1SwAccum	1P-start switch (IN1 bit2) edge accumulator; a pulse pays a credit + starts a 1P game
8005	start2SwAccum	2P-start switch (IN1 bit1) edge accumulator; starts a 2P game
8007	frameCounterPrescaler	/60 down-divider; on rollover reloads 60 and ticks playPhaseCounter
8009	frameWaitCountdown	Per-frame countdown decremented by the vblank NMI; armed + busy-waited to 0 by the frame-wait
800a	loopCounter	General loop down-counter (setup-repeat, screen-hold); also the board-complete bonus count 5/10/15
800d	prngLow	16-bit LFSR PRNG state, low byte — also the returned random draw
800e	prngHigh	PRNG state high byte
8010	playPhaseCounter	Board-startup ramp + master gate: enemies 1&2 run at >=8, enemy-3 + mountain erosion at >=0x0a
8011	mainLoopDelay	Per-frame busy-wait length = loopDelayBase - level; wraps to a ~17x crawl at level 10
8015	in1Debounced	Debounced IN1 (coin/start): stable value latched after two equal reads of 0xa800
8016	in1Prev	Previous IN1 sample, rolled each frame for the debounce compare
8018	in0Debounced	Debounced IN0 (joystick + dig/fire); movement/action code reads this, not the raw port
8019	in0Prev	Previous IN0 sample, rolled for the debounce
801a	playerAnimPhase	Player packed animation/command phase (wind-up countdown high bits, move command low bits)
801b	demoSteerDir	Attract-demo synthetic steering (one-hot 01/02/04/08); read in place of the stick at gameState >=3
801c	creditMirrorA	Redundant copy of creditCount, cross-checked by the corruption watchdog
801e	soundHead	Sound-command ring WRITE/head index (mod 8)
801f	soundTail	Sound-command ring READ/dequeue index (mod 8)
8020	soundRing	Sound-command ring buffer base (8 slots); enqueue writes (code ors 0x80) at head
8028	level	Current player's level/round counter (inits 1, +1 per clear); every difficulty subsystem scales off it
802b	menLeft	Active player's working lives; game-over gate is this reaching 0 (P1/P2 backups 802c/802d kept hex)
8031	scoreLo	Low packed-BCD byte of the active score (all score is displayed x100)
8034	scoreHi	High packed-BCD byte of the active score, paired with 8031
8037	scoreDisplayLow	Low byte of a 16-bit score value staged per high-score record for digit unpacking
8038	scoreDisplayHigh	High byte of that staged 16-bit score value
8039	highScoreTable	Base/top rank of the descending 3-entry high-score table (5-byte records: 3 initials + 16-bit value)
8048	variant	Board/entry variant selector read at round setup and by the fill dispatch (role weakly pinned)
804b	initialsRemaining	High-score initials-entry down-counter (seeded 3, ->0 ends entry)
804c	coinsPerCreditA	DSW coin cost for coin line 2 (0 = free play)
804d	coinsPerCreditB	DSW coin cost for coin line 3
804e	loopDelayBase	DSW main-loop pacing base that mainLoopDelay derives from
804f	stepTimerBase	DSW-decoded base that seeds the mountain-erosion step timer (804f - 4*level)
8051	spriteCoordBias	flipBit<<1 (= 0x02 when flipped): a +2 sprite-Y nudge, NOT the screen flip itself
8053	startingMen	DSW starting lives ((dsw&0x40)?4:3); seeds menLeft
8055	plotRunLength	Run length (cells) for the shared down-column tile/colour plotter
8057	boardMode	Board/entry-select mode byte the multi-door entry family stows before the shared body
8058	tileCol	Tile-cell COLUMN byte fed to the (row,col)->tilemap-offset calc
8059	tileRow	Tile-cell ROW byte fed to the tilemap-offset calc
805a	tilemapOffset	16-bit tilemap offset 32*row+col; consumed to derive the colour/video write cursors
805c	glitterCountdown	Free-running 8->1 countdown pacing the jewel-glitter cell recolour
805e	colourRamCursor	16-bit colour-RAM write cursor (tilemap offset + 0x8800), walked down-column by the fillers
8065	mountainErodePtr	16-bit VRAM cursor for mountain erosion (seed 0x9104, +0x20/step writing tile 0x31)
8067	mountainErodeTimer	Per-step erosion countdown, armed level-scaled (804f - 4*level, faster every level)
8068	playerY	Player Y (game-space work-Y); renders screen-HORIZONTAL under ROT270; drives the tilemap row
8069	playerFacing	Player facing + sprite-frame code (bit7 = horizontal mirror); selects the laser direction
806a	playerSpriteAttr	Player sprite attribute byte (palette bits0-2 + priority bit3)
806b	playerX	Player X (game-space work-X); renders screen-VERTICAL under ROT270; drives the tilemap column
806c	playerStepY	Player per-frame Y step, added to / subtracted from playerY
806d	playerStepX	Player per-frame X step, added to / subtracted from playerX
806e	playerCellPtr	16-bit pointer to the player's current video-RAM display cell
8071	playerTileCol	Tilemap COLUMN cell under the player (from playerX>>3); low part of the 806e cell pointer
8073	playerTileRow	Tilemap ROW cell under the player (from playerY); *0x20 major part of the 806e cell pointer
8076	prizeGate	Latch set by under-tile 0x26 — the prerequisite that unlocks the diamond pickup (NOT the 0x27 goal path)
8077	pitCrossActive	Sticky Pit-crossing flag set at goal tile 0x27; gates boarding the ship + disables the laser; awards no points
8078	treasureCollected	Set nonzero on a diamond pickup; the top-rung completion gate reads it (byte also reused by dig/twin-actor — coupling unproven)
8079	playerActive	Presence flag for the player object (0 none / 0xff present)
807b	boardEndPhase	End-of-board state when the mountain is gone: 0 idle / 1 escape (-> rescue ship -> level advance) / >=2 done
807c	transitionTimer	Master board-transition countdown; on expiry vectors to lose-a-life OR advance-a-level
807d	postTransitionMode	Death-vs-advance selector read at transitionTimer expiry: 0 lose a life / 1 advance a level
807e	carveSeamLeft	Flag set when a dug channel abuts the object's tile column on one side (left/right assignment rotation-ambiguous)
807f	carveSeamRight	Mirror seam flag for the opposite move arm
8080	moveBlockFlag	Movement blocker: a falling rock/arrow overlapping the player sets it and freezes climbing (hazards block, don't kill)
8081	crystalCount	Crystals collected (tile 0x3a); award +1000 displayed; board-complete bonus threshold ==4 (4 per board)
8082	diamondCount	Diamonds collected (tiles 0x3b/3c/3d); award +2000 displayed; bonus threshold ==3 (3 per board)
8084	enemyWorkSprite	Sprite/orientation byte of whichever enemy is ldir'd into the shared work slot; enemy-catch sets 0x17
8089	probeCellPtr	16-bit tilemap cell pointer (base 0x9000) the enemy tile-probe helpers deref +-0x20/row
808b	enemyActionTimer	Mover-record cadence/dwell countdown every mover routine drives (record offset 8)
808d	subtilePhase	Sub-tile phase / probe-table row index derived from the enemy's pixel position
8090	enemyWorkState	Signed state byte of the enemy in the work slot; also the laser-kill death marker (parked 0xc0 -> respawn)
8091	enemyWorkMovePeriod	Working-block mover cadence reload period
8092	enemyWorkDir	Published travel-direction index (0/1/2/3) stamped by the four direction presets
8093	enemyWorkTargetCol	Working-block mover target column it steers toward
8094	reactionObjX	playerY-paired position of the reaction/laser sprite entity (sprite record byte0); box-tested vs enemies
8095	reactionObjCode	Sprite/frame-code byte (byte1) of the reaction object's record
8096	reactionObjAttr	Attribute/anim byte (byte2) of the reaction record
8097	reactionObjY	playerX-paired position of the reaction/laser entity (sprite record byte3)
809a	laserScanPtr	16-bit tilemap cell the horizontal laser/terrain-scan walker samples (steps -0x20/frame)
809e	scrollSubphase	Sub-tile column phase selecting the ROM stop-tile slice for the laser/scroll
80a1	laserState	Laser-bolt state: 0 ready / +8 flying right / 0xf8 flying left / 1 spent (one bolt in flight)
80a2	reactionState	Per-object reaction/animation selector: 0 idle, 1-4 a collision/dig/push reaction armed; also a busy-lock
80a4	reactionTimer	Reaction step/animation countdown (reload from period 80a3); value 0x18 cues a sound
80a5	curTile	Saved current tile under the object
80a7	expectedTile	The object cell's table-resolved expected tile; cross-checked vs curTile to detect a change
80a8	nextTile	Next-tile slot, pre-cleared before classify
80a9	hazardX	X of the falling-hazard / dig-carve target cell (shared record; bbox-compared vs the player)
80aa	hazardState	State/phase AND sprite SHAPE of the falling-hazard/dig object: 0x10 falling (down-arrow) / 0x30 resting / 0x09 done
80ab	hazardType	Falling-hazard COLOUR (not glyph): 0x06 rock / 0x07 arrow — same shape, different palette; resting seed = 0x07
80ac	hazardY	Y of the same hazard record; advances +1/frame while falling
80b1	digObjTimer	Dig-carve object countdown/animation timer; shared — also the falling-hazard lifetime
80b6	stagedTargetX	Staged X coord (reactionObjX-4) promoted into hazardX at commit
80b9	stagedTargetY	Staged Y coord (playerX grid-snapped) promoted into hazardY at commit
80ba	stagedCellPtr	16-bit copy of playerCellPtr saved at spawn, reloaded into the live carve cursor at commit
80bc	stagedDigTimer	Staged dig timer (reactionPeriod<<1) promoted into digObjTimer at commit
80bd	hazardActiveCount	Number of falling hazards currently live (0 = none); bounds the drop machinery
80bf	stagedDigSpriteId	Staged classified dig-entity id, stamped into the tilemap cell before the carve cursor at commit
80c0	digObjSubtype	Sub-type of the committed dig entity (0 plain / 2 special: arm timer + patch neighbour tiles to 0xc1)
80c1	digCollisionState	Arm/capture state of the carve object (0 idle / 1 armed / 2 latched); gates dispatch
80c3	dropQueue	Base of the 24-slot pending-spawn column queue (12 left paired to 12 right)
80db	chamberCreatureX	Left-chamber creature X (byte0); horizontal bounce in [0x19,0x38) (velocity 80df)
80dc	chamberCreatureFrame	Creature sprite frame toggled 0x38<->0x39 every 8 frames
80dd	chamberCreatureAttr	Creature sprite byte2 attribute (color low bits + priority)
80de	chamberCreatureFallY	Creature's own accelerating fall-Y (step 80e0), clamped 0x86 then RNG-reseeded (drops and resets; no separate shell)
80e3	chamberCreatureAnimPhase	Creature frame-clock down-counter mod 8; reloads 8 on wrap, toggles the frame
80e4	pitFloorRevealPeriod	Level-derived reload period (7..3) for the Pit sliding-floor reveal gate
80e5	pitFloorRevealGate	Per-column frame-gate down-counter; on wrap reveals one Pit floor column
80e6	pitFloorRevealCursor	Byte offset into tile-pattern table 0x3048, stepped back 6 per reveal (==0 = reveal finished)
80e7	goalTileLatch	Latch set when the player reaches goal tile 0x27; reroutes state dispatch + enables the floor reveal
80e8	enemy1X	Base (offset 0, X) of enemy-1's 17-byte record
80e9	enemy1Sprite	Enemy-1 record byte1: sprite code + flipX/flipY orientation
80ea	enemy1Attr	Enemy-1 record offset 2: attr/color (priority bit3 held clear while color-cycling)
80f0	enemy1Timer	Enemy-1 mover cadence/dwell countdown (record offset 8)
80f5	enemy1State	Enemy-1 mover signed state byte the mover sign-dispatches on (offset 13)
80f6	enemy1MovePeriod	Enemy-1 mover cadence reload period = 7 - (level&6) (periodic mod 8, not monotonic)
80f8	enemy1TargetCol	Enemy-1 mover target column (record offset 16)
80f9	enemy2X	Base (offset 0, X) of enemy-2's 17-byte record
80fa	enemy2Sprite	Enemy-2 record offset 1 sprite tile/code byte
80fb	enemy2Attr	Enemy-2 record offset 2 attr/color byte
8101	enemy2Timer	Enemy-2 mover cadence/dwell countdown (mirror of enemy1Timer)
8106	enemy2State	Enemy-2 mover signed state byte (mirror of enemy1State)
8107	enemy2MovePeriod	Enemy-2 mover cadence reload period (mirror of enemy1MovePeriod)
8109	enemy2TargetCol	Enemy-2 mover target column (seed 5)
810a	enemy3X	Enemy-3 primary-half X (offset 0); a 2-sprite actor, also intro set-piece + escape rescue-ship (NOT a plain ship)
810b	enemy3Tile	Enemy-3 primary-half sprite/tile field
810c	enemy3Attr	Enemy-3 primary record byte+2 (color bits0-2 + priority bit3)
810d	enemy3Y	Enemy-3 primary-half Y
810e	enemy3StepX	Low byte of the actor's 16-bit step vector, added to enemy3X each cadence tick
810f	enemy3StepY	High byte of the actor step vector, added to enemy3Y each cadence tick
8112	enemy3Timer	Enemy-3 cadence timer (record offset 8)
811b	enemy3TwinX	Enemy-3 twin-half X, locked +16 to enemy3X
811c	enemy3TwinTile	Enemy-3 twin-half sprite/tile field
811d	enemy3TwinAttr	Enemy-3 twin record byte+2 (color + priority)
811e	enemy3TwinY	Enemy-3 twin-half Y (record offset +3)
8123	enemy3TwinTimer	Enemy-3 twin cadence countdown (twin of enemy3Timer)
812c	creditMirrorB	Third redundant copy of creditCount, watchdog-read
8134	savedCellPtr	16-bit scratch holding a tilemap cell pointer (save/restore within the enemy neighbour-search)
8220	spriteStagingBase	Base of the 32-byte (8x4) sprite-record staging buffer the NMI copies to sprite RAM 0x9840
8238	enemy3SpriteSlot	Sprite-staging slot 6 (base+24), the actor body's record
823c	enemy3TwinSpriteSlot	Sprite-staging slot 7 (base+28), the twin's record
8280	scoreReadoutStrip	Base of a 32-cell work-RAM strip staging the on-screen score-readout column