Optimized pattern / song advance code. Prepared release 1.1.

Further optimized ADSR code

README.md

@@ -1,7 +1,7 @@
 # Raspberry Casket
 A fast and small open source Pretracker replayer
 
-## Raspberry Casket Player V1.0 (26-Dec-2022)
+## Raspberry Casket Player V1.1 (28-Dec-2022)
 
 Provided by Chris 'platon42' Hodges <chrisly@platon42.de>
 
@@ -83,12 +83,15 @@ The original code compressed with *Blueberry's* Shrinkler goes from
 18052 bytes down to 9023 bytes.
 
 Raspberry Casket, depending on the features compiled in, is about
-6374 bytes and goes down to ~4410 bytes (in isolation).
+6216 bytes and goes down to ~4348 bytes (in isolation).
 
 So this means that the optimization is not just "on the outside".
 
 ### Timing
 
+Sample generation is a bit faster (I guess around 10-15%), but most of the time is spent on muls operations, so this is the limiting factor.
+Raspberry Casket is about twice as fast as the old replayer for playback.
+
 Unfortunately, the replayer is still pretty slow and has high
 jitter compared to other standard music replayers.
 
@@ -99,3 +102,36 @@ about 34 on average!).
 
 Watch out for *Presto*, the [LightSpeedPlayer](https://github.com/arnaud-carre/LSPlayer) variant that should
 solve this problem.
+
+### Known issues
+
+- Behaviour for undefined volume slides with both up- and down nibble specified is different (e.g. A9A, hi Rapture!). Don't do that.
+- Don't use loops with odd lengths and offsets (even if Pretracker allows this when dragging the loop points).
+- Don't stop the music with F00 and use a note delay (EDx) in the same line.
+- Don't try to play music with no waves, instruments or patterns.
+- Pattern breaks with target row >= $7f will be ignored.
+- Shinobi seemed to have used an early beta version of Pretracker where it was possible to specify a Subloop Wait of 0. That's illegal and unsupported.
+- Pattern break (Dxx) + Song pos (Bxx) on the same line does not work in original Pretracker & Player: New Dxx position is ignored. 
+  There is code to enable it in the player, so you could in theory make backwards running tracks like in Protracker. 
+  But this doesn't make sense as long as the tracker itself does not support it.
+
+## Changelog
+
+### V1.1 (28-Dec-22)
+- Optimized base displacement by reordering variables.
+- Further optimized ADSR code.
+- Optimized wave loop code.
+- Bake in this strange vibrato speed multiplication to precalculated vibrato value (where possible).
+- Various small optimizations.
+- Store instrument number * 4 on loading to avoid using two adds every frame.
+- Optimized speed/shuffle code. Idea of using xor turned out to make things too complicated for pattern breaks/jumps.
+- Rearranged code for more short branches.
+- Optimized track delay code further.
+- Optimized pattern / song advance code.
+- Maximum jitter now about one rasterline less, average about 0.5 rasterlines less (measurements, your mileage may vary).
+- Drop-in replacement code size: 6228 bytes.
+
+### V1.0 (26-Dec-22)
+ 
+- Initial release.
+- Drop-in replacement code size: 6446 bytes.

binaries/readme.txt

@@ -1,5 +1,5 @@
 This file "raspberry_casket.bin" can replace the original "player.bin"
 provided that you used the 16 KB + 16 KB allocation for player
-variables as in the original player.
+variables as in the original player (you need only about 2 + 12 KB).
 
-It has been assembled from src/drop_in_replacement.asm.
+It has been assembled from src/drop_in_replacement.asm (version V1.1).

example/readme.txt

@@ -3,7 +3,7 @@ It features Pink's song Plastic Dove (from the Coda Intro).
 
 Even though it features the full replayer code and tune,
 the replayer including my demo framework and the song only
-takes a mere 6560 bytes (shrinkled), which is even smaller
+takes a mere 6448 bytes (shrinkled), which is even smaller
 than the new streaming replayer used in Pink's new streaming
 player demonstrated (closed source) in
 
@@ -11,7 +11,7 @@ https://www.pouet.net/prod.php?which=91551
 
 which is 6860 bytes.
 
-The Raspberry Casket replayer takes an average of 14
+The Raspberry Casket replayer takes an average of 13.5
 rasterlines while Pink's new streaming player takes
 only about 10 rasterlines.