The code is derived from Spectre PoC
https://github.com/crozone/SpectrePoC/tree/master

Transitive:

This source code originates from the example code provided in the
"Spectre Attacks: Exploiting Speculative Execution" paper found at
https://spectreattack.com/spectre.pdf

Minor modifications have been made to fix compilation errors and
improve documentation where possible.

Also includes snippets from the meltdown PoC (see meotdown/COPYING)
