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Tetris (NES, Nintendo)/RAM map
The following article is a RAM map for Tetris (NES, Nintendo).
| 0017 | random seed byte 0 |
| 0018 | random seed byte 1 |
| 0019 | PieceID of last nextpiece generated by rng |
| 001A | number of pieces this poweron |
| 0033 | spun on in wait4vbl loop at AA37 |
| 0040 | cur piece x |
| 0041 | cur piece y |
| 0042 | cur PieceID |
| 0044 | current speed level |
| 0045 | fall timer |
| 0046 | left/right autorepeat timer |
| 0047 | starting speed level |
| 0048 | Current game phase: 1 - active time 2 - start of spawn delay; update bg tilemap 3 - line clear check 4 - wait for line clear animation 5 - update score counter, etc. 6 - A-Type: dummy frame; B-Type: goal check 7 - normally a dummy frame -- contains logic for unfinished 2 player mode 8 - end of spawn delay; prepare next piece |
| 0049 | counter for bg tilemap update (used when 0048 == 2) |
| 004A-004D | line numbers being cleared |
| 004E | down autorepeat timer |
| 004F | down hold timer (cleared to 0 on release) |
| 0050-0051 | number of lines (BCD little endian) |
| 0053-0055 | score (little endian bcd) |
| 0052 | line clear animation counter (incremented when frame counter 00B1 % 4 == 0) |
| 0056 | number of lines being cleared |
| 0057 | line clear check counter (used when 0048 == 3) |
| 0058 | game over animation (negative: delay; $00: top; $14: finish) |
| 0059 | B-type height level |
| 0060-007F | mirror of 40-5F. If 00BE is forced to equal 2, this block is used for the unfinished 2 player mode. |
| 00A8 | copyright notice autoadvance time left |
| 00AC | same as 0042/0062 for collision? |
| 00AD | Playfield base address of current piece for collision? |
| 00AE | Y position of current piece in spritespace |
| 00B1-00B2 | demo time: 00B2 set to 0 when title screen appears; goes to demo at 00B5 = 5 |
| 00B5 | Bits set for 1 frame when NES Controller buttons are initially pressed (ABsSUDLR) |
| 00B6 | NES Controller button states (ABsSUDLR) |
| 00BE | Number of players. Always 1 by default, but forcing it to 2 enables unfinished 2 player Versus functionality. |
| 00BF | PieceID of next piece |
| 00C1 | game type (marathon = 0, 25lines = 1) |
| 00C2 | music type (sugarplum = 0, off = 3) |
| 00C3 | copyright notice unskippable time left |
| 00F5 | controller 1 newly pressed buttons |
| 00F7 | controller 1 state (0x80 = A pressed, 0x40 = B pressed...) |
| 00FC | vertical scroll (conjecture based on code at $80C5) |
| 00FD | horizontal scroll (conjecture based on code at $80C5) |
| 00FE | PPUMASK value |
| 00FF | PPUCTRL value |
| 0200 | Copy of OAM |
| 03F0-03F1 | number of T tetrominoes dealt (little endian BCD) |
| 03F2-03F3 | number of J tetrominoes dealt |
| 03F4-03F5 | number of Z tetrominoes dealt |
| 03F6-03F7 | number of O tetrominoes dealt |
| 03F8-03F9 | number of S tetrominoes dealt |
| 03FA-03FB | number of L tetrominoes dealt |
| 03FC-03FD | number of I tetrominoes dealt |
| 0400-0409 | Row $00 (top of playfield) |
| 040A-0413 | Row $01 |
| 04BE-04C7 | Row $13 (bottom) |
| 0680-06CF | Music related |
| 06D0-06FF | Sound effects related |
| 0700-075x | high score tables |
| 0718-071D | B-type top name |
| 071E-0723 | B-type second name |
| 0724-0729 | B-type third name |
PieceID
A PieceID is a number representing both a tetromino and an orientation. For instance, $11 is a I up and down, and $12 is an I across. Tetrominoes S, Z, and I have two PieceIDs; O has only one. The others have four. Because the PieceID table is "optimized" in this way, it'll take more extensive asm hacking to get Bombliss or Tetris DS rotation in.
The next piece is stored at $00BF. Poking a value into $00BF that's a valid PieceID but is not the starting orientation for that tetromino results in the next piece being drawn as a solid (not textured) O tetromino, but the next piece is dealt in the proper starting orientation.
Copy of OAM
At $0200 is a copy of OAM, the display list. Usually the falling piece occupies $0200-$020F, and the next piece occupies $0210-$021F.