improve the new ins format idea

papers/newIns.md

@@ -4,46 +4,75 @@ the main issue with Furnace instrument files is that they are too big, even if t
 
 the aim of this new format is to greatly reduce the size of a resulting instrument.
 
+# header
+
 ```
 size | description
 -----|------------------------------------
-  6  | "FURINS" format magic
+  4  | "FINS" format magic
   2  | format version
-  1  | instrument type
- ??? | feature bits
-  4  | instrument length (if wave/sample bits are on)
+  2  | instrument type
+ ??? | features...
 ```
 
-the "feature bits" field is a variable length bitfield. bit 7 in a byte indicates "read one more byte".
+a feature uses the following format:
 
-the feature bits are:
+```
+size | description
+-----|------------------------------------
+  2  | feature code
+  2  | length of block
+ ??? | data...
+```
 
-- 0: has wavetables
-- 1: has samples
-- 2: has name
-- 3: FM data
-- 4: FM data size (1: 2-op, 0: 4-op)
-- 5: FM data includes OPL/OPZ data
-  - if off, only read an op until ssgEnv.
-  - if on, read everything else.
-- 6: Game Boy data
-- 7: (continue in next byte)
-- 8: C64 data
-- 9: Amiga data
-- 10: standard data (macros)
-- 11: operator macros
-- 12: release points
-- 13: op release points
-- 14: extended op macros
-- 15: (continue in next byte)
-- 16: OPL drums mode data
-- 17: Amiga sample map data
-- 18: Namco 163 data
-- 19: extra macros
-- 20: FDS data
-- 21: OPZ data
-- 22: wavetable synth data
-- 23: (continue in next byte)
-- 24: additional macro modes
-- 25: extra C64 data
-- 26: MultiPCM data
+the following feature codes are recognized:
+
+- `FM`: FM ins data
+- `MA`: macro data
+- `64`: C64 ins data
+- `GB`: Game Boy ins data
+- `SM`: sample ins data
+- `O1`: operator 1 macros
+- `O2`: operator 2 macros
+- `O3`: operator 3 macros
+- `O4`: operator 4 macros
+- `LD`: OPL drums mode data
+- `SN`: SNES ins data
+- `N1`: Namco 163 ins data
+- `FD`: FDS ins data
+- `WS`: wavetable synth data
+- `SL`: list of samples
+- `WL`: list of wavetables
+- `MP`: MultiPCM ins data
+- `SU`: Sound Unit ins data
+- `ES`: ES5506 ins data
+
+# FM data (FM)
+
+```
+size | description
+-----|------------------------------------
+  1  | operator count
+-----|------------------------------------
+     | **base data**
+     | /7 6 5 4 3 2 1 0|
+  1  | |x| ALG |x| FB  |
+  1  | |FMS2 |AMS| FMS |
+  1  | |AM2|4| LLPatch |
+  1  | |KV4|KV3|KV2|KV1|
+-----|------------------------------------
+     | **operator data × opCount**
+     | /7 6 5 4 3 2 1 0|
+  1  | |r| D T |  MULT |
+     |  \- KSR
+  1  | |s|     T L     |
+     |  \- SUS
+  1  | |R S|v|   A R   |
+     |      \- VIB
+  1  | |A|KSL|   D R   |
+     |  \- AM
+  1  | |e|x|     D2R   |
+     |  \- EGT
+  1  | |  S L  |  R R  |
+  1  | |  DVB  |  SSG  |
+  1  | | DAM |   W S   |