The old speed scaling of 24 was ill-chosen so that triplets resulted in a minor buffer overflow error. This was never caught by anyone until Visual Studio 2019 in debug mode. Presumably all compilers allocate some extra space so this didn't matter. Now 29 increments = double speed and speeds with alternating 52 and 81 result in triplets that are just slightly faster then ordinary bpm i.e. the buffer will be slightly underrun, which probably is unnoticable to the user.
Builds on both 32-bit and 64-bit executables and all tests (except gm.dls stuff obviously, which was excluded) pass on 64-bit Linux. Cannot test the 32-bit executables, as WSL does not support running 32-bit.
The stereo opcode variants have bit 1 of the command stream set. The polyphony is split into two parts: 1) polyphony, meaning that voices reuse the same opcodes; 2) multitrack voices, meaning that a track triggers more than voice. They both can be flexible defined in any combinations: for example voice 1 and 2 can be triggered by track 1 and use instrument 1, and voice 3 by track 2/instrument 2 and voice 4 by track 3/instrument 2. This is achieved through the use of bitmasks: in the aforementioned example, bit 1 of su_voicetrack_bitmask would be set, meaning "the voice after voice #1 will be triggered by the same track". On the other hand, bits 1 and 3 of su_polyphony_bitmask would be set to indicate that "the voices after #1 and #3 will reuse the same instruments".
The modulation is now always added during value transformation.
With this, a lot of *_MOD defines could be removed.
The waveform for some tests changed slightly, because when the
value is saved to memory after modulating it, there is some
rounding errors.
