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# Tetris (NES, Nintendo)/ROM map

The following article is a ROM map for Tetris (NES, Nintendo).

All addresses are in CPU address space, not iNES file space. Subtract \$7FF0 for addresses within the iNES file, or use a more sophisticated algorithm for addresses within the UNIF file.

```; Code:

reset           = \$FF00
main            = \$8000
soundWaitVBL    = \$AA45  ; Run sound code and wait for vblank NMI
turnOnNMI       = \$AA6B  ; Turn on interrupt at scanline 241
turnOffNMI      = \$AA78  ; Turn off interrupt at scanline 241
clearNametable  = \$AA82  ; Clear nametable whose base address is A
clearVRAM       = \$AC1C  ; If A < \$1F, clear Y pages of VRAM to X
; Otherwise, clear 4 pages of VRAM to X and clear attribute table to Y
clearRAM        = \$AC6A  ; Clear pages X to Y of CPU RAM to value in A
switch          = \$AC82  ; Jumps to the Ath 16-bit address in the following jump table,
; similar to the "magic jump" in Super Mario Bros.
playSound       = \$E000  ; Appears to be sound code, called every frame
spawn           = \$988E  ; Spawn the next piece

; Data:
rotationTable   = \$88EE  ; Actually 2 tables interlaced: evens for CCW and odds for CW rotation.
; Determines the next piece+orientation value based off the current value.
tetriminoTable  = \$8A9C  ; Each piece is encoded as a sequence of 12 bytes that can be broken down
; into triplets (Y, tile, X) describing each square within the piece. Hex
; coordinate values above \$7F represent negative integers (\$FF = −1 and \$FE = −2).
garbageLines    = \$9B53  ; In the nonfinished 2 player vs mode, this is the number of lines to add to the opponent player
; 00 00 01 02 04
spawnTable1     = \$993B  ; 00 00 00 00 01 01 01 01 02 02 03 04 04 05 05 05 05 06 06
; Maps index into tetriminoTable to Tetrimino type.
spawnTable2     = \$994E  ; 02 07 08 0A 0B 0E 12; offsets into tetriminoTable for spawning each Tetrimino type
spawnTable3     = \$9956  ; 02 02 02 02 07 07 07 07 08 08 0A 0B 0B 0E 0E 0E 0E 12 12
; Maps index into tetriminoTable to the spawn orientation.
scoreIncTable   = \$9CA5  ; 40 00 00 01 00 03 00 12 (1 = 40, 2 = 100, 3 = 300, 4 = 1200); read by 9C3B: LDA \$9CA5,X
columnClears    = \$97FE  ; Sequence used during the clear animation: 04 03 02 01 00, 05 06 07 08 09
levelNumTable   = \$96B8  ; 00 01 02 03 ... 26 27 28 29; the code erroneously reads past this table for level 30+
LevelSpeedTable = \$898E  ; 30 2B 26 21 ... 02 01 01 01; Level speeds. Number of frames before a piece drops for each successive level.
initHiScores    = \$AD67  ; High score table, copied to \$0700 on boot
```