В ходе обсуждения обходных путей работы на процессорах x86, не поддерживающих инструкцию “cmpxchg8b”, Линус Торвальдс stated that it is time to declare the presence of this instruction to be mandatory for the nucleus and refuse to support i486 processors that do not support” CMPXCHG8B “, instead of trying to emulate this instructions on processors that no one is no longer Uses. Currently, almost all Linux distributions that continue the support of 32-bit X86 systems have switched to assembly of the nucleus with the X86_PAE option, which requires support for “CMPXCHG8B”.
by opinion Linus in terms of support In the nucleus, I486 processors lost their relevance, despite the fact that they are still found in everyday life. At a certain point, processors become museum exhibits and for them it is quite possible to get by with “museum” nuclei. Users who have systems with i486 processors will be able to use LTS nuclei letters, which will be accompanied by many more years.
The termination of the support of classic i486 will not affect the Intel manufactured by the built -in QUARK processors, which, although they relate to class I486, include additional instructions that are characteristic of the Pentium generation, including CMPXCHG8B. The same applies to the Vortex86DX processors. I386 processors support was stopped in the nucleus 10 years ago.