ITTECH.TXT defines the structure of the .IT file format, various notes on
reading files, handling effects, and other extremely useful information about
writing an IT player. Straight from Jeffrey Lim, it is the definitive reference
on how to implement the format successfully.
Following is a nearly verbatim copy of ITTECH.TXT as taken from Impulse Tracker
2.14p5. The only changes were to split it into sections.
## Impulse Header Layout
```txt
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───┬───┬───┬───┬───────────────────────────────────────────────┐
0000: │'I'│'M'│'P'│'M'│ Song Name, max 26 characters, includes NULL │
├───┴───┴───┴───┴───────────────────────────────────────┬───────┤
0010: │.......................................................│PHiligt│
├───────┬───────┬───────┬───────┬───────┬───────┬───────┼───────┤
0020: │OrdNum │InsNum │SmpNum │PatNum │ Cwt/v │ Cmwt │ Flags │Special│
├───┬───┼───┬───┼───┬───┼───────┼───────┴───────┼───────┴───────┤
0030: │GV │MV │IS │IT │Sep│PWD│MsgLgth│Message Offset │ Reserved │
├───┴───┴───┴───┴───┴───┴───────┴───────────────┴───────────────┤
0040: │ Chnl Pan (64 bytes)...........................................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤
0080: │ Chnl Vol (64 bytes)...........................................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤
00C0: │ Orders, Length = OrdNum │
├───────────────────────────────────────────────────────────────┤
xxxx: │ 'Long' Offset of instruments, Length = InsNum*4 (1) │
├───────────────────────────────────────────────────────────────┤
xxxx: │ 'Long' Offset of samples headers, Length = SmpNum*4 (2) │
├───────────────────────────────────────────────────────────────┤
xxxx: │ 'Long' Offset of patterns, Length = PatNum*4 (3) │
└───────────────────────────────────────────────────────────────┘
(1) Offset = 00C0h+OrdNum
(2) Offset = 00C0h+OrdNum+InsNum*4
(3) Offset = 00C0h+OrdNum+InsNum*4+SmpNum*4
Note that if the (long) offset to a pattern = 0, then the
pattern is assumed to be a 64 row empty pattern.
PHiliht = Pattern row hilight information. Only relevant for pattern
editing situations.
Cwt: Created with tracker.
Impulse Tracker y.xx = 0yxxh
Cmwt: Compatible with tracker with version greater than value.
(ie. format version)
OrdNum: Number of orders in song.
InsNum: Number of instruments in song
SmpNum: Number of samples in song
PatNum: Number of patterns in song
Flags: Bit 0: On = Stereo, Off = Mono
Bit 1: Vol0MixOptimizations - If on, no mixing occurs if
the volume at mixing time is 0 (redundant v1.04+)
Bit 2: On = Use instruments, Off = Use samples.
Bit 3: On = Linear slides, Off = Amiga slides.
Bit 4: On = Old Effects, Off = IT Effects
Differences:
- Vibrato is updated EVERY frame in IT mode, whereas
it is updated every non-row frame in other formats.
Also, it is two times deeper with Old Effects ON
- Command Oxx will set the sample offset to the END
of a sample instead of ignoring the command under
old effects mode.
- (More to come, probably)
Bit 5: On = Link Effect G's memory with Effect E/F. Also
Gxx with an instrument present will cause the
envelopes to be retriggered. If you change a
sample on a row with Gxx, it'll adjust the
frequency of the current note according to:
NewFrequency = OldFrequency * NewC5 / OldC5;
Bit 6: Use MIDI pitch controller, Pitch depth given by PWD
Bit 7: Request embedded MIDI configuration
(Coded this way to permit cross-version saving)
Special: Bit 0: On = song message attached.
Song message:
Stored at offset given by "Message Offset" field.
Length = MsgLgth.
NewLine = 0Dh (13 dec)
EndOfMsg = 0
Note: v1.04+ of IT may have song messages of up to
8000 bytes included.
Bit 1: Reserved
Bit 2: Reserved
Bit 3: MIDI configuration embedded
Bit 4-15: Reserved
GV: Global volume. (0->128) All volumes are adjusted by this
MV: Mix volume (0->128) During mixing, this value controls
the magnitude of the wave being mixed.
IS: Initial Speed of song.
IT: Initial Tempo of song
Sep: Panning separation between channels (0->128, 128 is max sep.)
PWD: Pitch wheel depth for MIDI controllers
Chnl Vol: Volume for each channel. Ranges from 0->64
Chnl Pan: Each byte contains a panning value for a channel. Ranges from
0 (absolute left) to 64 (absolute right). 32 = central pan,
100 = Surround sound.
+128 = disabled channel (notes will not be played, but note
that effects in muted channels are
still processed)
Orders: This is the order in which the patterns are played.
Valid values are from 0->199.
255 = "---", End of song marker
254 = "+++", Skip to next order
```
## Old Impulse Instrument Format (cmwt < 200h)
```txt
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───┬───┬───┬───┬───────────────────────────────────────────────┐
0000: │'I'│'M'│'P'│'I'│ DOS FileName (12345678.123) │
├───┼───┼───┼───┼───┬───┬───┬───┬───────┬───┬───┬───────┬───┬───┤
0010: │00h│Flg│VLS│VLE│SLS│SLE│ x │ x │FadeOut│NNA│DNC│TrkVers│NoS│ x │
├───┴───┴───┴───┴───┴───┴───┴───┴───────┴───┴───┴───────┴───┴───┤
0020: │ Instrument Name, max 26 bytes, includes NUL...................│
├───────────────────────────────────────┬───┬───┬───┬───┬───┬───┤
0030: │.......................................│ x │ x │ x │ x │ x │ x │
├───────────────────────────────────────┴───┴───┴───┴───┴───┴───┤
0040: │ Note-Sample/Keyboard Table, Length = 240 bytes................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤
0130: │ Volume envelope (200 bytes)...................................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
├───┴───┴───┴───┴───┴───┴───┴───┤
01F8: │ Node points (25x2 bytes)......│
└───────────────────────────────┘
Total length of old instrument header is 554 bytes.
Flg: Bit 0. On = Use volume envelope
Bit 1. On = Use volume loop
Bit 2. On = Use sustain volume loop
VLS: Volume loop start (node number)
VLE: Volume loop end (node number)
SLS: Sustain loop start (node number)
SLE: Sustain loop end (node number)
FadeOut: Ranges between 0 and 64, but the fadeout "Count" is 512.
Fade applied when:
1) Note fade NNA is selected and triggered (by another note)
2) Note off NNA is selected with no volume envelope
or volume envelope loop
3) Volume envelope end is reached
DNC: Duplicate note check (0 = Off, 1 = On)
NNA: New note action:
0 = Note cut
1 = Note continue
2 = Note off
3 = Note fade
TrkVers: Tracker version used to save the instrument. This is only
used in the instrument files.
NoS: Number of samples associated with instrument. This is only
used in the instrument files.
Note-Sample/Keyboard Table.
Each note of the instrument is first converted to a sample number
and a note (C-0 -> B-9). These are stored as note/sample pairs
(note first, range 0->119 for C-0 to B-9, sample ranges from
1-99, 0=no sample)
Volume envelope: Values from 0->64, 0FFh indicating end of envelope.
(after which note fade applies)
Node data: Tick THEN magnitude
```
## Impulse Instrument Format
```txt
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───┬───┬───┬───┬───────────────────────────────────────────────┐
0000: │'I'│'M'│'P'│'I'│ DOS FileName (12345678.123) │
├───┼───┼───┼───┼───────┬───┬───┬───┬───┬───┬───┬───────┬───┬───┤
0010: │00h│NNA│DCT│DCA│FadeOut│PPS│PPC│GbV│DfP│RV │RP │TrkVers│NoS│ x │
├───┴───┴───┴───┴───────┴───┴───┴───┴───┴───┴───┴───────┴───┴───┤
0020: │ Instrument Name, max 26 bytes, includes NUL...................│
├───────────────────────────────────────┬───┬───┬───┬───┬───────┤
0030: │.......................................│IFC│IFR│MCh│MPr│MIDIBnk│
├───────────────────────────────────────┴───┴───┴───┴───┴───────┤
0040: │ Note-Sample/Keyboard Table, Length = 240 bytes................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤
0130: │ Envelopes.....................................................│
├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤
IFC = Initial Filter cutoff
IFR = Initial Filter resonance
NNA = New Note Action
0 = Cut 1 = Continue
2 = Note off 3 = Note fade
DCT = Duplicate Check Type
0 = Off 1 = Note
2 = Sample 3 = Instrument
DCA: Duplicate Check Action
0 = Cut
1 = Note Off
2 = Note fade
FadeOut: Ranges between 0 and 128, but the fadeout "Count" is 1024
See the Last section on how this works.
Fade applied when:
1) Note fade NNA is selected and triggered (by another note)
2) Note off NNA is selected with no volume envelope
or volume envelope loop
3) Volume envelope end is reached
PPS: Pitch-Pan separation, range -32 -> +32
PPC: Pitch-Pan center: C-0 to B-9 represented as 0->119 inclusive
GbV: Global Volume, 0->128
DfP: Default Pan, 0->64, &128 => Don't use
RV: Random volume variation (percentage)
RP: Random panning variation (panning change - not implemented yet)
MCh = MIDI Channel
MPr = MIDI Program (Instrument)
TrkVers: Tracker version used to save the instrument. This is only
used in the instrument files.
NoS: Number of samples associated with instrument. This is only
used in the instrument files.
Note-Sample/Keyboard Table.
Each note of the instrument is first converted to a sample number
and a note (C-0 -> B-9). These are stored as note/sample byte pairs
(note first, range 0->119 for C-0 to B-9, sample ranges from
1-99, 0=no sample)
```
#### Envelope layout
```txt
Envelopes: 3 structures, first for volume (130h), second for
panning (182h), third for pitch (1D4h).
Each is structured as such:
0 1 2 3 4 5 6.......
┌───┬───┬───┬───┬───┬───┬───────────────────────────────────┬───┐
xxxx: │Flg│Num│LpB│LpE│SLB│SLE│ Node points, 25 sets, 75 bytes....│ x │
├───┼───┼───┼───┼───┼───┼───┬───┬───┬───┬───┬───┬───┬───┬───┼───┤
Flg: Bit 0: Envelope on/off, 1 = on, 0 = off
Bit 1: Loop on/off, 1 = on, 0 = off
Bit 2: SusLoop on/off, 1 = on, 0 = off
For Pitch envelope only:
Bit 7: Use pitch envelope as filter envelope instead.
Num = Number of node points
LpB = Loop beginning SLB = Sustain loop beginning
LpE = Loop end SLE = Sustain loop end
Node point = 1 byte for y-value
(0->64 for vol, -32->+32 for panning or pitch)
1 word (2 bytes) for tick number (0->9999)
Total length of an instrument is 547 bytes, but 554 bytes are
written, just to simplify the loading of the old format. (Hence
there are 7 'wasted' bytes per instrument)
```
## Impulse Sample Format
```txt
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───┬───┬───┬───┬───────────────────────────────────────────────┐
0000: │'I'│'M'│'P'│'S'│ DOS Filename (12345678.123) │
├───┼───┼───┼───┼───────────────────────────────────────────────┤
0010: │00h│GvL│Flg│Vol│ Sample Name, max 26 bytes, includes NUL.......│
├───┴───┴───┴───┴───────────────────────────────────────┬───┬───┤
0020: │.......................................................│Cvt│DfP│
├───────────────┬───────────────┬───────────────┬───────┴───┴───┤
0030: │ Length │ Loop Begin │ Loop End │ C5Speed │
├───────────────┼───────────────┼───────────────┼───┬───┬───┬───┤
0040: │ SusLoop Begin │ SusLoop End │ SamplePointer │ViS│ViD│ViR│ViT│
└───────────────┴───────────────┴───────────────┴───┴───┴───┴───┘
The cache file has the following pieces of information added on:
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───────────────┬───────┬───────┬───┬───────────────────────────┐
0050: │ File Size │ Date │ Time │Fmt│...........................│
└───────────────┴───────┴───────┴───┴───────────────────────────┘
Fmt. 0 = unchecked. 1 = directory, 2 = it sample, 3 = st sample
GvL: Global volume for instrument, ranges from 0->64
Flg: Bit 0. On = sample associated with header.
Bit 1. On = 16 bit, Off = 8 bit.
Bit 2. On = stereo, Off = mono. Stereo samples not supported yet
Bit 3. On = compressed samples.
Bit 4. On = Use loop
Bit 5. On = Use sustain loop
Bit 6. On = Ping Pong loop, Off = Forwards loop
Bit 7. On = Ping Pong Sustain loop, Off = Forwards Sustain loop
Vol: Default volume for instrument
Length: Length of sample in no. of samples NOT no. of bytes
LoopBeg: Start of loop (no of samples in, not bytes)
Loop End: Sample no. AFTER end of loop
C5Speed: Number of bytes a second for C-5 (ranges from 0->9999999)
SusLBeg: Start of sustain loop
SusLEnd: Sample no. AFTER end of sustain loop
SmpPoint: 'Long' Offset of sample in file.
ViS: Vibrato Speed, ranges from 0->64
ViD: Vibrato Depth, ranges from 0->64
ViT: Vibrato waveform type.
0=Sine wave
1=Ramp down
2=Square wave
3=Random (speed is irrelevant)
ViR: Vibrato Rate, rate at which vibrato is applied (0->64)
The depth of the vibrato at any point is worked out in the following
way:
Every processing cycle, the following occurs:
1) Mov AX, [SomeVariableNameRelatingToVibrato]
2) Add AL, Rate
3) AdC AH, 0
4) AH contains the depth of the vibrato as a fine-linear slide.
5) Mov [SomeVariableNameRelatingToVibrato], AX ; For the next
; cycle.
For those that don't understand assembly, then the depth is
basically the running-sum of the rate divided by 256.
Sample vibrato uses a table 256-bytes long
Convert - bits other than bit 0 are used internally for the loading
of alternative formats.
Bit 0:
Off: Samples are unsigned } IT 2.01 and below use unsigned samples
On: Samples are signed } IT 2.02 and above use signed samples
Bit 1:
Off: Intel lo-hi byte order for 16-bit samples } Safe to ignore
On: Motorola hi-lo byte order for 16-bit samples } these values...
Bit 2: }
Off: Samples are stored as PCM values }
On: Samples are stored as Delta values }
Bit 3: }
On: Samples are stored as byte delta values }
(for PTM loader) }
Bit 4: }
On: Samples are stored as TX-Wave 12-bit values }
Bit 5: }
On: Left/Right/All Stereo prompt }
Bit 6: Reserved
Bit 7: Reserved
DfP - Default Pan. Bits 0->6 = Pan value, Bit 7 ON to USE (opposite of inst)
```
## Impulse Pattern Format
```txt
0 1 2 3 4 5 6 7 8 9 A B C D E F
┌───────┬───────┬───┬───┬───┬───┬───────────────────────────────┐
0000: │Length │ Rows │ x │ x │ x │ x │ Packed data................ │
├───┬───┼───┬───┼───┼───┼───┼───┼───┬───┬───┬───┬───┬───┬───┬───┤
Length: Length of packed pattern, not including the 8 byte header
Note that the pattern + the 8 byte header will ALWAYS
be less than 64k
Rows: Number of rows in this pattern (Ranges from 32->200)
Patterns are unpacked by the following pseudocode... (this may look
horrible, but in practise, it's just as convenient as the S3M
pattern format for playback (but not for display))
GetNextChannelMarker:
Read byte into channelvariable.
if(channelvariable = 0) then end of row
Channel = (channelvariable-1) & 63 ; Channel is 0 based.
if(channelvariable & 128) then read byte into maskvariable
else maskvariable = previousmaskvariable for current channel
if(maskvariable & 1), then read note. (byte value)
// Note ranges from 0->119 (C-0 -> B-9)
// 255 = note off, 254 = notecut
// Others = note fade (already programmed into IT's player
// but not available in the editor)
if(maskvariable & 2), then read instrument (byte value)
// Instrument ranges from 1->99
if(maskvariable & 4), then read volume/panning (byte value)
// Volume ranges from 0->64
// Panning ranges from 0->64, mapped onto 128->192
// Prepare for the following also:
// 65->74 = Fine volume up
// 75->84 = Fine volume down
// 85->94 = Volume slide up
// 95->104 = Volume slide down
// 105->114 = Pitch Slide down
// 115->124 = Pitch Slide up
// 193->202 = Portamento to
// 203->212 = Vibrato
Effects 65 is equivalent to D0F, 66 is equivalent to D1F -> 74 = D9F
Similarly for 75-84 (DFx), 85-94 (Dx0), 95->104 (D0x).
(Fine) Volume up/down all share the same memory (NOT shared with Dxx
in the effect column tho).
Pitch slide up/down affect E/F/(G)'s memory - a Pitch slide
up/down of x is equivalent to a normal slide by x*4
Portamento to (Gx) affects the memory for Gxx and has the equivalent
slide given by this table:
SlideTable DB 1, 4, 8, 16, 32, 64, 96, 128, 255
Vibrato uses the same 'memory' as Hxx/Uxx.
if(maskvariable & 8), then read command (byte value) and commandvalue
// Valid ranges from 0->31 (0=no effect, 1=A, 2=B, 3=C, etc.)
if(maskvariable & 16), then note = lastnote for channel
if(maskvariable & 32), then instrument = lastinstrument for channel
if(maskvariable & 64), then volume/pan = lastvolume/pan for channel
if(maskvariable & 128), then {
command = lastcommand for channel and
commandvalue = lastcommandvalue for channel
}
Goto GetNextChannelMarker
```
## Mathematics
```txt
Abbreviations:
FV = Final Volume (Ranges from 0 to 128). In versions 1.04+, mixed output
devices are reduced further to a range from 0 to 64 due to lack of
memory.
Vol = Volume at which note is to be played. (Ranges from 0 to 64)
SV = Sample Volume (Ranges from 0 to 64)
IV = Instrument Volume (Ranges from 0 to 128)
CV = Channel Volume (Ranges from 0 to 64)
GV = Global Volume (Ranges from 0 to 128)
VEV = Volume Envelope Value (Ranges from 0 to 64)
In Sample mode, the following calculation is done:
FV = Vol * SV * CV * GV / 262144 ; Note that 262144 = 2^18
; So bit shifting can be done.
In Instrument mode the following procedure is used:
1) Update volume envelope value. Check for loops / end of envelope.
2) If end of volume envelope (ie. position >= 200 or VEV = 0FFh), then turn
on note fade.
3) If notefade is on, then NoteFadeComponent (NFC) = NFC - FadeOut
; NFC should be initialised to 1024 when a note is played.
4) FV = Vol * SV * IV * CV * GV * VEV * NFC / 2^41
Linear slides work like this:
Final frequency = Original frequency * 2^(SlideValue/768)
(I used a lookup table for the multipliers here)
For command Exx, SlideValue = -4*EffectValue
For command EEx, SlideValue = -EffectValue
For command Fxx, SlideValue = 4*EffectValue
For command FEx, SlideValue = EffectValue
Note that sample vibrato always uses Linear slides.
Notes about effects (as compared to other module formats)
C This is now in *HEX*. (Used to be in decimal in ST3)
E/F/G/H/U You need to check whether the song uses Amiga/Linear slides.
H/U Vibrato in Impulse Tracker is two times finer than in
any other tracker and is updated EVERY tick.
If "Old Effects" is *ON*, then the vibrato is played in the
normal manner (every non-row tick and normal depth)
E/F/G These commands ALL share the same memory.
Oxx Offsets to samples are to the 'xx00th' SAMPLE. (ie. for
16 bit samples, the offset is xx00h*2)
Oxx past the sample end will be ignored, unless "Old Effects"
is ON, in which case the Oxx will play from the end of the
sample.
Yxy This uses a table 4 times larger (hence 4 times slower) than
vibrato or tremelo. If the waveform is set to random, then
the 'speed' part of the command is interpreted as a delay.
If you read through this document and there are ANY points which you have
troubles with (and have to try out), then let me know - because someone
else will have the same questions - and I'd like to make this DOC as easy
to understand as possible.
For Panning....
Here's the rough procedure used:
NotePan = ChannelPan
if InstrumentPan=On then NotePan = InstrumentPan
NotePan = NotePan+(InstrumentNote-PPCenter)*PPSeparation/8
Pitch Envelopes
Each value on the envelope equates to half a semitone. This is interpolated
64 times for smooth pitch sliding. Positive values indicate a pitch variation
UP of x semitones, negative values indicate a pitch variation down.
```
## General Info
```txt
The player in Impulse Tracker 'allocates' channels to notes whenever they
are *PLAYED*. In sample mode, the allocation is simple:
Virtual Channel (number) = 'Host' channel (number)
In instrument mode, the following procedure is used:
Check if channel is already playing ---Yes--> set 'background' flag on.
| 'Trigger' NNA. If NNA=cut,
No then use this virtual
| channel.
| |
|<------------------ else -----------------/
|
v
Search and find the first non-active virtual channel.
|
Non-active channel found? ----Yes----> Use this for playback.
|
No
|
v
Search through and find the channel of lowest volume that is in the #
'background' (ie. no longer controlled directly) #
| #
Background channel found? ----Yes----> Use this for playback. #
| #
No #
| #
v #
Return error - the note is *NOT* allocated a channel, and hence is not #
played. #
This is actually quite a simple process... just that it's another of
those 'hassles' to have to write...
### Note: This is by far the simplest implementation of congestion
resolution. IT 2.03 and above have a greatly enhanced
method which more selectively removes the most insignificant
channel. Obviously, there is no best way to do this - I
encourage you to experiment and find new algorithms for
yourself.
```
## Internal Tables
```txt
FineSineData Label Byte
DB 0, 2, 3, 5, 6, 8, 9, 11, 12, 14, 16, 17, 19, 20, 22, 23
DB 24, 26, 27, 29, 30, 32, 33, 34, 36, 37, 38, 39, 41, 42, 43, 44
DB 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59
DB 59, 60, 60, 61, 61, 62, 62, 62, 63, 63, 63, 64, 64, 64, 64, 64
DB 64, 64, 64, 64, 64, 64, 63, 63, 63, 62, 62, 62, 61, 61, 60, 60
DB 59, 59, 58, 57, 56, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46
DB 45, 44, 43, 42, 41, 39, 38, 37, 36, 34, 33, 32, 30, 29, 27, 26
DB 24, 23, 22, 20, 19, 17, 16, 14, 12, 11, 9, 8, 6, 5, 3, 2
DB 0, -2, -3, -5, -6, -8, -9,-11,-12,-14,-16,-17,-19,-20,-22,-23
DB -24,-26,-27,-29,-30,-32,-33,-34,-36,-37,-38,-39,-41,-42,-43,-44
DB -45,-46,-47,-48,-49,-50,-51,-52,-53,-54,-55,-56,-56,-57,-58,-59
DB -59,-60,-60,-61,-61,-62,-62,-62,-63,-63,-63,-64,-64,-64,-64,-64
DB -64,-64,-64,-64,-64,-64,-63,-63,-63,-62,-62,-62,-61,-61,-60,-60
DB -59,-59,-58,-57,-56,-56,-55,-54,-53,-52,-51,-50,-49,-48,-47,-46
DB -45,-44,-43,-42,-41,-39,-38,-37,-36,-34,-33,-32,-30,-29,-27,-26
DB -24,-23,-22,-20,-19,-17,-16,-14,-12,-11, -9, -8, -6, -5, -3, -2
FineRampDownData Label Byte
DB 64, 63, 63, 62, 62, 61, 61, 60, 60, 59, 59, 58, 58, 57, 57, 56
DB 56, 55, 55, 54, 54, 53, 53, 52, 52, 51, 51, 50, 50, 49, 49, 48
DB 48, 47, 47, 46, 46, 45, 45, 44, 44, 43, 43, 42, 42, 41, 41, 40
DB 40, 39, 39, 38, 38, 37, 37, 36, 36, 35, 35, 34, 34, 33, 33, 32
DB 32, 31, 31, 30, 30, 29, 29, 28, 28, 27, 27, 26, 26, 25, 25, 24
DB 24, 23, 23, 22, 22, 21, 21, 20, 20, 19, 19, 18, 18, 17, 17, 16
DB 16, 15, 15, 14, 14, 13, 13, 12, 12, 11, 11, 10, 10, 9, 9, 8
DB 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0
DB 0, -1, -1, -2, -2, -3, -3, -4, -4, -5, -5, -6, -6, -7, -7, -8
DB -8, -9, -9,-10,-10,-11,-11,-12,-12,-13,-13,-14,-14,-15,-15,-16
DB -16,-17,-17,-18,-18,-19,-19,-20,-20,-21,-21,-22,-22,-23,-23,-24
DB -24,-25,-25,-26,-26,-27,-27,-28,-28,-29,-29,-30,-30,-31,-31,-32
DB -32,-33,-33,-34,-34,-35,-35,-36,-36,-37,-37,-38,-38,-39,-39,-40
DB -40,-41,-41,-42,-42,-43,-43,-44,-44,-45,-45,-46,-46,-47,-47,-48
DB -48,-49,-49,-50,-50,-51,-51,-52,-52,-53,-53,-54,-54,-55,-55,-56
DB -56,-57,-57,-58,-58,-59,-59,-60,-60,-61,-61,-62,-62,-63,-63,-64
FineSquareWave Label Byte
DB 128 Dup (64), 128 Dup (0)
EmptyPattern Label
DW 64, 64, 0, 0
DB 64 Dup (0)
;───────────────────────────────────────────────────────────────────────────────
PitchTable Label DWord ; Values are 16.16 bit
DW 2048, 0, 2170, 0, 2299, 0, 2435, 0, 2580, 0, 2734, 0 ; C-0
DW 2896, 0, 3069, 0, 3251, 0, 3444, 0, 3649, 0, 3866, 0 ;>B-0
DW 4096, 0, 4340, 0, 4598, 0, 4871, 0, 5161, 0, 5468, 0 ; C-1
DW 5793, 0, 6137, 0, 6502, 0, 6889, 0, 7298, 0, 7732, 0 ;>B-1
DW 8192, 0, 8679, 0, 9195, 0, 9742, 0, 10321, 0, 10935, 0
DW 11585, 0, 12274, 0, 13004, 0, 13777, 0, 14596, 0, 15464, 0
DW 16384, 0, 17358, 0, 18390, 0, 19484, 0, 20643, 0, 21870, 0
DW 23170, 0, 24548, 0, 26008, 0, 27554, 0, 29193, 0, 30929, 0
DW 32768, 0, 34716, 0, 36781, 0, 38968, 0, 41285, 0, 43740, 0
DW 46341, 0, 49097, 0, 52016, 0, 55109, 0, 58386, 0, 61858, 0
DW 0, 1, 3897, 1, 8026, 1, 12400, 1, 17034, 1, 21944, 1
DW 27146, 1, 32657, 1, 38496, 1, 44682, 1, 51236, 1, 58179, 1
DW 0, 2, 7794, 2, 16051, 2, 24800, 2, 34068, 2, 43888, 2
DW 54292, 2, 65314, 2, 11456, 3, 23828, 3, 36936, 3, 50823, 3
DW 0, 4, 15588, 4, 32103, 4, 49600, 4, 2601, 5, 22240, 5
DW 43048, 5, 65092, 5, 22912, 6, 47656, 6, 8336, 7, 36110, 7
DW 0, 8, 31176, 8, 64205, 8, 33663, 9, 5201, 10, 44481, 10
DW 20559, 11, 64648, 11, 45823, 12, 29776, 13, 16671, 14, 6684, 15
DW 0, 16, 62352, 16, 62875, 17, 1790, 19, 10403, 20, 23425, 21
DW 41118, 22, 63761, 23, 26111, 25, 59552, 26, 33342, 28, 13368, 30
FineLinearSlideUpTable Label ; Values are 16.16 bit
DW 0, 1, 59, 1, 118, 1, 178, 1, 237, 1 ; 0->4
DW 296, 1, 356, 1, 415, 1, 475, 1, 535, 1 ; 5->9
DW 594, 1, 654, 1, 714, 1, 773, 1, 833, 1 ; 10->14
DW 893, 1 ; 15
LinearSlideUpTable Label ; Value = 2^(Val/192), Values are 16.16 bit
DW 0, 1, 237, 1, 475, 1, 714, 1, 953, 1 ; 0->4
DW 1194, 1, 1435, 1, 1677, 1, 1920, 1, 2164, 1 ; 5->9
DW 2409, 1, 2655, 1, 2902, 1, 3149, 1, 3397, 1 ; 10->14
DW 3647, 1, 3897, 1, 4148, 1, 4400, 1, 4653, 1 ; 15->19
DW 4907, 1, 5157, 1, 5417, 1, 5674, 1, 5932, 1 ; 20->24
DW 6190, 1, 6449, 1, 6710, 1, 6971, 1, 7233, 1 ; 25->29
DW 7496, 1, 7761, 1, 8026, 1, 8292, 1, 8559, 1 ; 30->34
DW 8027, 1, 9096, 1, 9366, 1, 9636, 1, 9908, 1 ; 35->39
DW 10181, 1, 10455, 1, 10730, 1, 11006, 1, 11283,1 ; 40->44
DW 11560, 1, 11839, 1, 12119, 1, 12400, 1, 12682,1 ; 45->49
DW 12965, 1, 13249, 1, 13533, 1, 13819, 1, 14106,1 ; 50->54
DW 14394, 1, 14684, 1, 14974, 1, 15265, 1, 15557,1 ; 55->59
DW 15850, 1, 16145, 1, 16440, 1, 16737, 1, 17034,1 ; 60->64
DW 17333, 1, 17633, 1, 17933, 1, 18235, 1, 18538,1 ; 65->69
DW 18842, 1, 19147, 1, 19454, 1, 19761, 1, 20070,1 ; 70->74
DW 20379, 1, 20690, 1, 21002, 1, 21315, 1, 21629,1 ; 75->79
DW 21944, 1, 22260, 1, 22578, 1, 22897, 1, 23216,1 ; 80->84
DW 23537, 1, 23860, 1, 24183, 1, 24507, 1, 24833,1 ; 85->89
DW 25160, 1, 25488, 1, 25817, 1, 26148, 1, 26479,1 ; 90->94
DW 26812, 1, 27146, 1, 27481, 1, 27818, 1, 28155,1 ; 95->99
DW 28494, 1, 28834, 1, 29175, 1, 29518, 1, 29862,1 ; 100->104
DW 30207, 1, 30553, 1, 30900, 1, 31248, 1, 31599,1 ; 105->109
DW 31951, 1, 32303, 1, 32657, 1, 33012, 1, 33369,1 ; 110->114
DW 33726, 1, 34085, 1, 34446, 1, 34807, 1, 35170,1 ; 115->119
DW 35534, 1, 35900, 1, 36267, 1, 36635, 1, 37004,1 ; 120->124
DW 37375, 1, 37747, 1, 38121, 1, 38496, 1, 38872,1 ; 125->129
DW 39250, 1, 39629, 1, 40009, 1, 40391, 1, 40774,1 ; 130->134
DW 41158, 1, 41544, 1, 41932, 1, 42320, 1, 42710,1 ; 135->139
DW 43102, 1, 43495, 1, 43889, 1, 44285, 1, 44682,1 ; 140->144
DW 45081, 1, 45481, 1, 45882, 1, 46285, 1, 46690,1 ; 145->149
DW 47095, 1, 47503, 1, 47917, 1, 48322, 1, 48734,1 ; 150->154
DW 49147, 1, 49562, 1, 49978, 1, 50396, 1, 50815,1 ; 155->159
DW 51236, 1, 51658, 1, 52082, 1, 52507, 1, 52934,1 ; 160->164
DW 53363, 1, 53793, 1, 54224, 1, 54658, 1, 55092,1 ; 165->169
DW 55529, 1, 55966, 1, 56406, 1, 56847, 1, 57289,1 ; 170->174
DW 57734, 1, 58179, 1, 58627, 1, 59076, 1, 59527,1 ; 175->179
DW 59979, 1, 60433, 1, 60889, 1, 61346, 1, 61805,1 ; 180->184
DW 62265, 1, 62727, 1, 63191, 1, 63657, 1, 64124,1 ; 185->189
DW 64593, 1, 65064, 1, 0, 2, 474, 2, 950, 2 ; 190->194
DW 1427, 2, 1906, 2, 2387, 2, 2870, 2, 3355, 2 ; 195->199
DW 3841, 2, 4327, 2, 4818, 2, 5310, 2, 5803, 2 ; 200->204
DW 6298, 2, 6795, 2, 7294, 2, 7794, 2, 8296, 2 ; 205->209
DW 8800, 2, 9306, 2, 9814, 2, 10323, 2, 10835,2 ; 210->214
DW 11348, 2, 11863, 2, 12380, 2, 12899, 2, 13419,2 ; 215->219
DW 13942, 2, 14467, 2, 14993, 2, 15521, 2, 16051,2 ; 220->224
DW 16583, 2, 17117, 2, 17653, 2, 18191, 2, 18731,2 ; 225->229
DW 19273, 2, 19817, 2, 20362, 2, 20910, 2, 21460,2 ; 230->234
DW 22011, 2, 22565, 2, 23121, 2, 23678, 2, 24238,2 ; 235->239
DW 24800, 2, 25363, 2, 25929, 2, 25497, 2, 27067,2 ; 240->244
DW 27639, 2, 28213, 2, 28789, 2, 29367, 2, 29947,2 ; 245->249
DW 30530, 2, 31114, 2, 31701, 2, 32289, 2, 32880, 2 ; 250->254
DW 33473, 2, 34068, 2 ; 255->256
FineLinearSlideDownTable Label ; Values are 0.16 bit
DW 65535, 65477, 65418, 65359, 65300, 65241, 65182, 65359 ; 0->7
DW 65065, 65006, 64947, 64888, 64830, 64772, 64713, 64645 ; 8->15
LinearSlideDownTable Label ; Values are 0.16 bit
DW 65535, 65300, 65065, 64830, 64596, 64364, 64132, 63901 ; 0->7
DW 63670, 63441, 63212, 62984, 62757, 62531, 62306, 62081 ; 8->15
DW 61858, 61635, 61413, 61191, 60971, 60751, 60532, 60314 ; 16->23
DW 60097, 59880, 59664, 59449, 59235, 59022, 58809, 58597 ; 24->31
DW 58386, 58176, 57966, 57757, 57549, 57341, 57135, 56929 ; 32->39
DW 56724, 56519, 56316, 56113, 55911, 55709, 55508, 55308 ; 40->47
DW 55109, 54910, 54713, 54515, 54319, 54123, 53928, 53734 ; 48->55
DW 53540, 53347, 53155, 52963, 52773, 52582, 52393, 52204 ; 56->63
DW 52016, 51829, 51642, 51456, 51270, 51085, 50901, 50718 ; 64->71
DW 50535, 50353, 50172, 49991, 49811, 49631, 49452, 49274 ; 72->79
DW 49097, 48920, 48743, 48568, 48393, 48128, 48044, 47871 ; 80->87
DW 47699, 47527, 47356, 47185, 47015, 46846, 46677, 46509 ; 88->95
DW 46341, 46174, 46008, 45842, 45677, 45512, 45348, 45185 ; 96->103
DW 45022, 44859, 44698, 44537, 44376, 44216, 44057, 43898 ;104->111
DW 43740, 43582, 43425, 43269, 43113, 42958, 42803, 42649 ;112->119
DW 42495, 42342, 42189, 42037, 41886, 41735, 41584, 41434 ;120->127
DW 41285, 41136, 40988, 40840, 40639, 40566, 40400, 40253 ;128->135
DW 40110, 39965, 39821, 39678, 39535, 39392, 39250, 39109 ;136->143
DW 38968, 38828, 38688, 38548, 38409, 38271, 38133, 37996 ;144->151
DW 37859, 37722, 37586, 37451, 37316, 37181, 37047, 36914 ;152->159
DW 36781, 36648, 36516, 36385, 36254, 36123, 35993, 35863 ;160->167
DW 35734, 35605, 35477, 35349, 35221, 35095, 34968, 34842 ;168->175
DW 34716, 34591, 34467, 34343, 34219, 34095, 33973, 33850 ;176->183
DW 33728, 33607, 33486, 33365, 33245, 33125, 33005, 32887 ;184->191
DW 32768, 32650, 32532, 32415, 32298, 32182, 32066, 31950 ;192->199
DW 31835, 31720, 31606, 31492, 31379, 31266, 31153, 31041 ;200->207
DW 30929, 30817, 30706, 30596, 30485, 30376, 30226, 30157 ;208->215
DW 30048, 29940, 29832, 29725, 29618, 29511, 29405, 29299 ;216->223
DW 29193, 29088, 28983, 28879, 28774, 28671, 28567, 28464 ;224->231
DW 28362, 28260, 28158, 28056, 27955, 27855, 27754, 27654 ;232->239
DW 27554, 27455, 27356, 27258, 27159, 27062, 26964, 26867 ;240->247
DW 26770, 26674, 26577, 26482, 26386, 26291, 26196, 26102 ;248->255
DW 26008 ; 256
```
## Effect Info
```txt
Here's about all the info I can think of for effects. "Process" variables are
variables used internally by effects to control the direction of playback..
This section has not been completed yet.
First, here is the rough flow chart for processing information, it's not fully
detailed, but all of the important steps are outlined.
┌─────────────────────────────────────────────────────────┐
│ Set note volume to volume set for each channel │
│ Set note frequency to frequency set for each channel │
└────────────┬────────────────────────────────────────────┘
│
┌────────────┴────────────┐
│ Decrease tick counter │ Yes
│ Is tick counter 0 ? ├─────────────────────────┐
└────────────┬────────────┘ │
│ │
No │ ┌─────────────────────┴──────────────────┐
┌────────────┴────────────┐ │ Tick counter = Tick counter set │
│ Update effects for each │ │ (the current 'speed') │
│ channel as required. │ │ Decrease Row counter. │
│ │ │ Is row counter 0? │
└───┬─────────────────────┘ └────────────┬──────────┬────────────────┘
│ No │ │
│ ┌─────────────────────┘ │ Yes
│ │ │
│ ┌─────────────┴──────────────┐ ┌───────────────┴────────────────┐
│ │ Call update-effects for │ │ Row counter = 1 │
│ │ each channel. │ │ │
│ └──────────────┬─────────────┘ │ Increase ProcessRow │
│ │ │ Is ProcessRow > NumberOfRows? │
├─────────────────┘ └────────┬──────────────────┬────┘
│ Yes │ │ No
│ ┌────────────────────────────────┴──────────────┐ │
│ │ ProcessRow = BreakRow │ │
│ │ BreakRow = 0 │ │
│ │ Increase ProcessOrder │ │
│ │ while Order[ProcessOrder] = 0xFEh, │ │
│ │ increase ProcessOrder │ │
│ │ if Order[ProcessOrder] = 0xFFh, │ │
│ │ ProcessOrder = 0 │ │
│ │ CurrentPattern = Order[ProcessOrder] │ │
│ └─────────────────────┬─────────────────────────┘ │
│ │ │
│ ├─────────────────────────────┘
│ │
│ ┌─────────────────────┴──────────────────────────┐
│ │ CurrentRow = ProcessRow │
│ │ Update Pattern Variables (includes jumping to │
│ │ the appropriate row if requried and getting │
│ │ the NumberOfRows for the pattern) │
│ └─────────────────────┬──────────────────────────┘
│ │
├───────────────────────────────┘
│
┌───┴───────────────┐ Yes ┌───────────────────────────────┐
│ Instrument mode? ├──────────────────┤ Update Envelopes as required │
└───┬───────────────┘ │ Update fadeout as required │
│ │ Calculate final volume if req │
│ No (Sample mode) │ Calculate final pan if req │
│ │ Process sample vibrato if req │
┌───┴─────────────────────────────────┐└───────────────┬───────────────┘
│ Calculate final volume if required │ │
│ Calculate final pan if requried │ │
│ Process sample vibrato if required │ │
└───┬─────────────────────────────────┘ │
│ │
│ │
└─────────────────────────┬────────────────────────┘
│
┌────────────────┴──────────────────┐
│ Output sound!!! │
└───────────────────────────────────┘
Axx Set Tempo
if (xx != 0) {
Maxtick = xx;
Currenttick = xx;
}
Bxx Jump to Order
ProcessOrder = xx - 1;
ProcessRow = 0xFFFE; // indicates new pattern internally for IT...
Cxx Break to Row
BreakRow = xx;
ProcessRow = 0xFFFE;
Dxx Volume slide down
if (xx == 0) then xx = last xx for (Dxx/Kxx/Lxx) for this channel.
Order of testing: Dx0, D0x, DxF, DFx
Dx0 Set effect update for channel enabled if channel is ON.
If x = F, then slide up volume by 15 straight away also (for S3M compat)
Every update, add x to the volume, check and clip values > 64 to 64
D0x Set effect update for channel enabled if channel is ON.
If x = F, then slide down volume by 15 straight away also (for S3M)
Every update, subtract x from the volume, check and clip values < 0 to 0
DxF Add x to volume straight away. Check and clip values > 64 to 64
DFx Subtract x from volume straight away. Check and clip values < 0 to 0
Hxy Vibrato
if (x != 0) {
speed = 4*x;
}
if (y != 0) {
depth = y * 4;
if(OldEffects) depth <<= 1;
}
Set effect update for channel enabled if channel is ON.
Goto InitVibrato (explained later)
Ixy Tremor, ontime x, offtime y
if (x != 0) {
ontime = x;
if (oldeffects) ontime++;
}
if (y != 0) {
offtime = y;
if (oldeffects) offtime++;
}
Nxx Channel volume slide down
if (xx == 0) then xx = last Nxx for this channel.
Order of testing: Nx0, N0x, NxF, NFx
Nx0 Set effect update for channel enabled.
Every update, add x to the volume, check and clip values > 64 to 64
N0x Set effect update for channel enabled.
Every update, subtract x from the volume, check and clip values < 0 to 0
NxF Add x to volume straight away. Check and clip values > 64 to 64
NFx Subtract x from volume straight away. Check and clip values < 0 to 0
Uxy Fine Vibrato
if (x != 0) {
speed = 4*x;
}
if (y != 0) {
depth = y;
if(OldEffects) depth <<= 1;
}
Set effect update for channel enabled if channel is ON.
Goto InitVibrato (explained later)
Wxx Global volume slide down
if (xx == 0) then xx = last Wxx for this channel.
Order of testing: Wx0, W0x, WxF, WFx
Wx0 Set effect update for channel enabled.
Every update, add x to the volume, check and clip values > 128 to 128
W0x Set effect update for channel enabled.
Every update, subtract x from the volume, check and clip values < 0 to 0
WxF Add x to volume straight away. Check and clip values > 128 to 128
WFx Subtract x from volume straight away. Check and clip values < 0 to 0
.. sorry this is incomplete..
```