Tetris (NES) Music Format Addendum.txt

TETRIS (NES) MUSIC FORMAT ADDENDUM
v1.0

By Justin Olbrantz (Quantam)

The permanent home of this specification and others, with the latest updates, is https://github.com/TheRealQuantam/RetroDocs.

This document is an addendum to the Mother Music Format specification. Both games use the same engine and function identically, but many data tables differ, including note length (tempo) tables and key tables. This document provides the tables and addresses of data analogous to those in the Mother specification, to be used for the same purposes.

Bank configuration:
$c000-$ffff: Bank 1

1:ebaf byte[$74]: Note length table in frames

            0   1   2   3   4   5   6   7   8   9   a   b   c   d   e   f
    BPM    16   8   4   2   1  4D  2D  8D  4T  8T  32
0  (300):   3   6  12  24  48  18  36   9   8   4   2*  1
c  (225):   4   8  16  32  64  24  48  12  10*  5*  2   1
18 (180):   5  10  20  40  80  30  60  15  13*  6*  2*  1
24 (150):   6  12  24  48  96  36  72  18  16   8   3   1   4   2   0 144
34 (129):   7  14  28  56 112  42  84  21  18*  9*  3*  1   2
41 (113):   8  16  32  64 128  48  96  24  21* 10*  4   1   2 192
4f (100):   9  18  36  72 144  54 108  27  24    *   *
58 (90):   10  20  40  80 160 108 120  30  26* 13*  5   1   2  23
66 (82):   11  22  44  88 176  66 132  33  29* 14*  5*  1   2  23

Tetris has a very robust set of tempos even though only a few are actually used. It is identical to Mother's table except for the addition of 300 BPM tempo; even the missing lengths for 100 BPM are the same.

          Whole  Half   4th   8th  16th  32nd
Normal:       4    3      2     1     0     a*
Dotted:            6      5     7
Triplet:                  8*    9*

Code to load the current length for notes:
E907    LDA $EBAF,Y

Code to limit the triangle auto-release length to 15 frames ($3c quarter-frames) when in dynamic auto-release mode:
E9D0    CMP #$3C
E9D2    BCC $E9D6
E9D4    LDA #$3C

1:eb13 big-endian word[$4b]: Key pitch table, in period register units. For square wave channels, period = 1789773 / frequency / 16 - 1 (triangle channel is 1 octave lower). Entry 1 must be 0 as it is rest.

Oct  C  C#   D  D#   E   F  F#   G  G#   A  A#   B  Max Detune at B
1:                                       0          0.96 cents
2:   2   3   4   5   6   7   8   9   a   b   c   d  1.91 cents
3:   e   f  10  11  12  13  14  15  16  17  18  19  3.83 cents
4:  1a  1b  1c  1d  1e  1f  20  21  22  23  24  25  7.69 cents
5:  26  27  28  29  2a  2b  2c  2d  2e  2f  30  31  15.49 cents
6:  32  33  34  35  36  37  38  39  3a  3b  3c  3d  31.41 cents
7:  3e  3f  40  41  42  43  45  46  47  48      49  64.58 cents
8:  4a

Code to load the period for a melodic key:
E923    LDA $EB14,Y
...
E93E    LDA $EB14,Y
E941    STA $0680,X
E944    LDA $EB13,Y
E947    ORA #$08
E949    STA $0681,X

1:e5ab byte[$d]: Noise preset table. Actually begins at offset 1 ($e5ac). Valid presets are 4, 7, and $a.

Code to play a noise preset:
E9F0    LDA $E5AB,Y
E9F3    STA NoiseVolume_400C
E9F6    LDA $E5AC,Y
E9F9    STA NoisePeriod_400E
E9FC    LDA $E5AD,Y
E9FF    STA NoiseLength_400F

Tetris supports DMC and appears to have 2 presets, however this may be a coincidence as the music never uses them and the code to play DMC is identical to that of Mother even though the data at the specified addresses is completely different. The DMC addresses may in fact be pointing to random data that just happens to both sound vaguely kick drum-like.

EA03    TYA
EA04    AND #$C0
EA06    CMP #$40
EA08    BEQ $EA0F
EA0A    CMP #$80
EA0C    BEQ $EA19
EA0E    RTS
EA0F    LDA #$0E
EA11    STA $E1
EA13    LDA #$07
EA15    LDY #$00
EA17    BEQ $EA21
EA19    LDA #$0E
EA1B    STA $E1
EA1D    LDA #$0F
EA1F    LDY #$02
EA21    STA DmcLength_4013
EA24    STY DmcAddress_4012
EA27    LDA $06F7
EA2A    BNE $EA40
EA2C    LDA $E1
EA2E    STA DmcFreq_4010
EA31    LDA #$0F
EA33    STA ApuStatus_4015
EA36    LDA #$00
EA38    STA DmcCounter_4011
EA3B    LDA #$1F
EA3D    STA ApuStatus_4015
EA40    RTS

1:ea4a word[$16]: Volume envelope table. Indices are 0-based, unlike in the set timbre commands and the following table.

Envelope  1 @ea76: 4689877666554433222111 f0
Envelope  2 @ea82: 8655444431111111 f0
Envelope  3 @ea8b: 5443332211 f0
Envelope  4 @ea91: 2345776655444444 ff
Envelope  5 @ea9a: 32222222222222 ff
Envelope  6 @eaa2: 9981 ff
Envelope  7 @eaa5: 5871 ff
Envelope  8 @eaa8: e79981 ff
Envelope  9 @eaac: a8665554434332222221111111 f0
Envelope  a @eaba: 976544333333222211111111 f0
Envelope  b @eac7: 654444332222111111111111 f0
Envelope  c @ead4: 443322221111111111 f0
Envelope  d @eade: 222211111111111111 f0
Envelope  e @eae8: 976532432111322111 ff
Envelope  f @eaf2: d8765432 ff
Envelope 10 @eaf7: b8765321 ff
Envelope 11 @eafc: 85432111 ff
Envelope 12 @eb01: 532211 ff
Envelope 13 @eb05: eb975321 ff
Envelope 14 @eb0a: a991 f0
Envelope 15 @eb0d: 8551 f0
Envelope 16 @eb10: 6331 f0

Code to load an envelope address:
E785    LDA $EA4A,Y
E788    STA $E2
E78A    LDA $EA4B,Y
E78D    STA $E3

Tetris has the same set of pitch envelopes as Mother. For completeness here is the code:
E5FA    LDA $E2
E5FC    CMP #$31
E5FE    BNE $E602
E600    LDA #$27
E602    TAY
E603    LDA $E689,Y
E606    PHA
E607    LDA $06C3,X
E60A    CMP #$46
E60C    BNE $E613
E60E    PLA
E60F    LDA #$00
E611    BEQ $E671
E613    PLA
E614    JMP $E671
E617    LDA $E2
E619    TAY
E61A    CMP #$10
E61C    BCS $E624
E61E    LDA $E6C0,Y
E621    JMP $E677
E624    LDA #$F6
E626    BNE $E677
E628    LDA $06C3,X
E62B    CMP #$4C
E62D    BCC $E633
E62F    LDA #$FE
E631    BNE $E677
E633    LDA #$FE
E635    BNE $E677
...
E637    LDA $06D1,X <- starts here
E63A    STA $E2
E63C    LDA $E0
E63E    CMP #$20
E640    BEQ $E656
E642    CMP #$A0
E644    BEQ $E665
E646    CMP #$60
E648    BEQ $E628
E64A    CMP #$40
E64C    BEQ $E617
E64E    CMP #$80
E650    BEQ $E5FA
E652    CMP #$C0
E654    BEQ $E5FA
E656    LDA $E2
E658    CMP #$0A
E65A    BNE $E65E
E65C    LDA #$00
E65E    TAY
E65F    LDA $E6B6,Y
E662    JMP $E671
E665    LDA $E2
E667    CMP #$2B
E669    BNE $E66D
E66B    LDA #$21
E66D    TAY
E66E    LDA $E695,Y
E671    PHA
E672    TYA
E673    STA $06D1,X
E676    PLA
E677    PHA
E678    LDA $06C8,X
E67B    BNE $E687
E67D    PLA
E67E    CLC
E67F    ADC $E1
E681    LDY $EE
E683    STA Sq0Timer_4002,Y
E686    RTS

The code that determines whether a given envelope has the triangle "forever" flag set:
E9B9    LDA $069C
E9BC    AND #$C0
E9BE    BNE $E9C3
E9C0    TYA
E9C1    BNE $E9CB
E9C3    CMP #$C0
E9C5    BEQ $E9C0
E9C7    LDA #$FF

1:ec23 byte[$b]: Track header offset table. Indices are actually 0-based, unlike the numbers given.
1:ec2d struct[$b]: Track header block

Track 1 is hypothesized to be an unused title theme, and is used nowhere else in the game.

 1 Unused @ec2d:  +10  +24  ecf1  ecf5  ecf7  ecf9
  Square 1 @ecf1: ecff 0000
  Square 2 @ecf5: ed6f
  Triangle @ecf7: ede2
  Noise    @ecf9: ee6f

 2 Success @ec37:   -4   +0  ec91  ec95  ec97  ec99
  Square 1 @ec91: ec9b 0000
  Square 2 @ec95: ecc7
  Triangle @ec97: ecb1
  Noise    @ec99: ecdd

 3 Music 1 @ec41:   -2  +24  eebf  eec9  eed3  eedd
  Square 1 @eebf: | eee3 f0f0 f1de
  Square 2 @eec9: | efb1 f147 f1f7
  Triangle @eed3: | f04f f196 f242
  Noise    @eedd: | f258

 4 Music 2 @ec4b:   -4  +24  f5c2  f5d0  f5de  f5ec
  Square 1 @f5c2: | f5f8 f66a f686 f686 f6f2
  Square 2 @f5d0: | f5f2 f667 f6ac f6ac f795
  Triangle @f5de: | f606 f678 f6d2 f6d2 f833
  Noise    @f5ec: | f614

 5 Music 3 @ec55:   -2  +24  f2b1  f2b9  f2bf  ffff
  Square 1 @f2b1: f2cb | f2d4
  Square 2 @f2b9: | f2d1
  Triangle @f2bf: | f34d

 6 Fast Music 1 @ec5f:   -2   +0  eebf  eec9  eed3  eedd
  Square 1 @eebf: | eee3 f0f0 f1de
  Square 2 @eec9: | efb1 f147 f1f7
  Triangle @eed3: | f04f f196 f242
  Noise    @eedd: | f258

 7 Fast Music 2 @ec69:   -4   +c  f5c2  f5d0  f5de  f5ec
  Square 1 @f5c2: | f5f8 f66a f686 f686 f6f2
  Square 2 @f5d0: | f5f2 f667 f6ac f6ac f795
  Triangle @f5de: | f606 f678 f6d2 f6d2 f833
  Noise    @f5ec: | f614

 8 Fast Music 3 @ec73:   -2   +c  f2b1  f2b9  f2bf  ffff
  Square 1 @f2b1: f2cb | f2d4
  Square 2 @f2b9: | f2d1
  Triangle @f2bf: | f34d

 9 High Score @ec7d:   +0  +18  f3a4  f3aa  f3b0  f3b6
  Square 1 @f3a4: | f3bc
  Square 2 @f3aa: | f458
  Triangle @f3b0: | f530
  Noise    @f3b6: | f57f

 a Victory @ec87:  -16  +24  f89e  f8aa  f8b6  f8c2
  Square 1 @f89e: | f8f6 f96d f8f6 f9b7
  Square 2 @f8aa: | f8ce f947 f8ce f991
  Triangle @f8b6: | f90b f97f f90b f9d2
  Noise    @f8c2: | f920 f920 f920 f930

Code to load a track header:
E6E3    LDA $EC23,Y
E6E6    TAY
E6E7    LDX #$00
E6E9    LDA $EC2D,Y
E6EC    STA $0690,X
E6EF    INY
E6F0    INX
E6F1    TXA
E6F2    CMP #$0A
E6F4    BNE $E6E9