It's currently written for ASM6 and CA65 assemblers, with the purpose of providing a better balance between features, ROM size, and CPU usage. Compatible with FamiTracker TXT export.
Full features list / limitations can be read here:
https://github.com/CutterCross/Sabre
The main goal I had set out when writing this was to have a similar / improved feature set to GGsound while keeping the peak CPU usage as low as possible. The average CPU usage for music playback is on par with FamiTone2. Music data size is somewhere in-between GGsound and FamiTone2.
The replayer source is only built for ASM6 at the moment, as I don't have much experience with CA65 yet. The driver itself and exported music files are compatible across both assemblers, with separate RAM assignments specific to ASM6 and CA65.
I hope this will be of use to some people
