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Tetris (NES, Nintendo)/ROM map: Difference between revisions
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(Described tetrimino table.) |
(Added spawn table) |
||
| Line 21: | Line 21: | ||
; into triplets (Y, tile, X) describing each square within the piece. Hex | ; into triplets (Y, tile, X) describing each square within the piece. Hex | ||
; coordinate values above $7F represent negative integers ($FF = −1 and $FE = −2). | ; coordinate values above $7F represent negative integers ($FF = −1 and $FE = −2). | ||
spawnTable = $994E ; 02 07 08 0A 0B 0E 12; offsets into tetriminoTable for spawning each Tetrimino type | |||
scoreIncTable = $9CA5 ; 40 00 00 01 00 03 00 12 (1 = 40, 2 = 100, 3 = 300, 4 = 1200); read by 9C3B: LDA $9CA5,X | scoreIncTable = $9CA5 ; 40 00 00 01 00 03 00 12 (1 = 40, 2 = 100, 3 = 300, 4 = 1200); read by 9C3B: LDA $9CA5,X | ||
levelNumTable = $96B8 ; 00 01 02 03 ... 26 27 28 29; the code erroneously reads past this table for level 30+ | levelNumTable = $96B8 ; 00 01 02 03 ... 26 27 28 29; the code erroneously reads past this table for level 30+ | ||
Revision as of 01:43, 24 November 2013
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
; Data:
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).
spawnTable = $994E ; 02 07 08 0A 0B 0E 12; offsets into tetriminoTable for spawning each Tetrimino type
scoreIncTable = $9CA5 ; 40 00 00 01 00 03 00 12 (1 = 40, 2 = 100, 3 = 300, 4 = 1200); read by 9C3B: LDA $9CA5,X
levelNumTable = $96B8 ; 00 01 02 03 ... 26 27 28 29; the code erroneously reads past this table for level 30+
initHiScores = $AD67 ; High score table, copied to $0700 on boot