I am not sure which CPUs exactly the article is refering to with those early i586 CPUs, but I do remember those Cyrix 6x86/6x86MX CPUs. When it comes to Linux, they were always treated as 486-class CPUs because they were missing some instructions required to be considered 586-class. On the other hand their architecture was actually quite modern, like a 686 CPU with out-of-order execution. The 6x86MX also supported the CMOV instruction which is usually associated with 686-class CPU. Quite strange CPUs from today’s perspective.
VIA also had some CPUs (certain VIA C3 CPUs) that the Linux kernel always treated as 486-class CPUs due to some missing 586 instructions.
Then you have the NexGen Nx586, which is arguably 386-like in having no FPU, but ended up being the ancestor of most modern x86 CPUs by decomposing complex operations into RISC-esque micro-ops.
I am not sure which CPUs exactly the article is refering to with those early i586 CPUs, but I do remember those Cyrix 6x86/6x86MX CPUs. When it comes to Linux, they were always treated as 486-class CPUs because they were missing some instructions required to be considered 586-class. On the other hand their architecture was actually quite modern, like a 686 CPU with out-of-order execution. The 6x86MX also supported the CMOV instruction which is usually associated with 686-class CPU. Quite strange CPUs from today’s perspective.
VIA also had some CPUs (certain VIA C3 CPUs) that the Linux kernel always treated as 486-class CPUs due to some missing 586 instructions.
Then you have the NexGen Nx586, which is arguably 386-like in having no FPU, but ended up being the ancestor of most modern x86 CPUs by decomposing complex operations into RISC-esque micro-ops.