As of 2025 and much earlier, there were only 3 operating systems that mattered on desktop:We refer to them as "the three operating systems".
Each microarchitecture appears to fully specify all core parameters, it feels likely that they just reuse most of all of the RTL, or even pre-synthesize core blobs.
Bibliography:
- www.quantamagazine.org/how-smell-guides-our-inner-world-20250703/ How Smell Guides Our Inner World (2025)
Will we ever fully understand the brain? by 
Ciro Santilli 40 Created 2025-07-11 Updated 2025-07-16
Ciro Santilli 40 Created 2025-07-11 Updated 2025-07-16- journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1005268 Could a Neuroscientist Understand a Microprocessor? by Jonas and Kording (2017)
There are unlisted articles, also show them or only show them.