4k intro用シンセ制作の資料
https://qiita.com/MachiaWorx/items/87968666a2baf9fcc493
http://kioku.sys-k.net/tips/
http://gyabo.sakura.ne.jp/progsnd.html
https://qiita.com/MachiaWorx/items/a94504a6cce48c8ce4e7
https://github.com/in4k/andromedary_sources/blob/master/synth.h
https://github.com/in4k/faemiyah-demoscene_2015-08_4k-intro_ghosts_of_mars/blob/master/src/synth.c
https://github.com/in4k/faemiyah-demoscene_2014-08_4k-intro_whisky_in_a_tube/blob/master/src/chip.c
https://github.com/in4k/faemiyah-demoscene_2013-08_4k-intro_yog-sothoth/tree/master/src
https://www.agner.org/optimize/
https://basicsynth.com/index.php?page=basicsynthlib