The ACID engine's DSP (firmware/src/bass303.c, bass303.h, fastmath.h) is a C99 / single-precision / no-libm port of
Open303 by Robin Schmidt (RS-MET, https://www.rs-met.com, https://github.com/RobinSchmidt/Open303): the signal path and
the constants of its getSample() (pitch slew, the decay envelope and its two RC followers, the measured env-mod mapping, the
TB_303-mode TeeBeeFilter after mystran and kunn, its feedback highpass, the amp envelope, the 200 Hz de-clicker and the
allpass / highpass / notch after the filter). It reached Felucca by way of fm1-x0x's dsp/bass303.c (GPL-3.0-only; itself
after schwung-303, GPL-3.0, with the Devilfish ranges after jc303 by midilab and the RAT drive after davemollen/dm-Rat,
GPL-3.0). The ported files stay under the MIT licence below for the Open303 parts; the rest of Felucca, the x0x port and the
RAT drive model are GPL-3.0-only (LICENSE).

The licence of Open303 follows: the standard MIT text, with Robin Schmidt's name as the donor's headers give it. Upstream's
own LICENSE file also carries a year; this tree could not read that file (offline), so none is written here -- add it from
upstream before a release.

MIT License

Copyright (c) Robin Schmidt (RS-MET)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.