This patch adds the code necessary to perform basic buffer sampling for
HW voices. Includes new register definitions, support for a few new
methods, envelope stepping, ADPCM decoding, and the individual voice
buffer sampling to be added to the VP output mixbufs. This code does not
add system audio playback nor streaming support.
Some portions are disabled as they will need to be fixed up for
compilation in this new tree.
This code originates from Jannik Vogel's 2017 audio branch. Copied into
the current, recently LGPL-licensed version of this file with
permission.
https://github.com/JayFoxRox/xqemu-espes/commits/audio
Matt Borgerson