New Linux Patches Propose Removing Support For Old i486 & Early i586 CPUs
New Linux Patches Propose Removing Support For Old i486 & Early i586 CPUs
www.phoronix.com
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I guess that old hardware was always gonna go obsolete someday. I wonder how many are still in use
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I wonder if that new instructions are needed for anything useful.
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The patch series today though would end support for original i486 processors as well as early i586 processors. The kernel patches would remove support for CPUs lacking TSC and CX8/CMPXCHG8B capabilities. Basically this would put the minimum upstream Linux kernel support for 32-bit processors at the original Pentium CPU with CMPXCHG8B and Time Stamp Counter (TSC) support.
There were 586 CPUs that were not Pentiums? Article implies the original Pentium would be the new baseline, but then what 586 CPUs would lose support?
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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.
AMD's Am5x86 CPUs were rebranded 486 CPUs, while AMD's K5 was an early 586 CPU that might fall into that early 586 category due to missing instructions. AMD's later K6 CPUs should support all Pentium instructions afaik (but not CMOV like the Cyrix CPUs did).
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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.
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In addition to what others have said I would imagine the Pentium OverDrive would be among those losing support as well.
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15 comments