Amiga info.

Adding useful Amiga info to docs and chip selector.

doc/6-sample/README.md

@@ -47,7 +47,7 @@ use of this mode is discouraged in favor of Sample type instruments.
 
 due to limitations in some of those sound chips, some restrictions exist:
 
-- Amiga: sample lengths and loop will be set to an even number, and your sample can't be longer than 131070.
+- Amiga: maximum frequency is 31,469Hz, but anything over 28,867 will sound glitchy on hardware. sample lengths and loop will be set to an even number, and your sample can't be longer than 131070.
 - NES: if on DPCM mode, only a limited selection of frequencies is available, and loop position isn't supported (only entire sample).
 - SegaPCM: your sample can't be longer than 65535, and the maximum frequency is 31.25KHz.
 - QSound: your sample can't be longer than 65535, and the loop length shall not be greater than 32767.

doc/7-systems/amiga.md

@@ -15,3 +15,9 @@ imported MOD files use this chip, and will set A-4 tuning to 436.
   - does not work on the last channel.
 - `13xx`: **change wave.**
   - only works when "Mode" is set to "Wavetable" in the instrument.
+
+# info
+
+- the maximum rate for sample playback is technically 31,469Hz but anything higher than 28,867Hz will sound glitchy on hardware.
+- sample lengths and loop will be set to an even number.
+- samples can't be longer than 131070.

src/engine/sysDef.cpp

@@ -798,7 +798,7 @@ void DivEngine::registerSystems() {
 
   sysDefs[DIV_SYSTEM_AMIGA]=new DivSysDef(
     "Amiga", NULL, 0x81, 0, 4, false, true, 0, false, 1U<<DIV_SAMPLE_DEPTH_8BIT,
-    "a computer from the '80's with full sampling capabilities, giving it a sound ahead of its time.",
+    "a computer from the '80's with full sampling capabilities, giving it a sound ahead of its time.\n\n- the maximum rate for sample playback is technically 31,469Hz but anything higher than 28,867Hz will sound glitchy on hardware.\n- sample lengths and loop will be set to an even number.\n- samples can't be longer than 131070.",
     {"Channel 1", "Channel 2", "Channel 3", "Channel 4"},
     {"CH1", "CH2", "CH3", "CH4"},
     {DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM},