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Programmatically Detect if an i486 CPU has SL Enhanced Support

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First post, by red-ray

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While developing the SIV CPU i486 S-Spec panel I felt SIV should report if the CPU has SL Enhanced support so I added this by checking the i486 S-Specs data.

While doing this I started wondering, is there a defined way to detect if an i486 CPU has SL Enhanced support? I have tried Googling with thus far no luck. Ideally I would like to do this from ring 3 so prefer not to use CRn registers.

file.php?id=217893

I should also like to fill in the ?, if you have a i486 with a S-Spec that has them please let me know what they should be. The dates should be printed on the CPU and SIV should report the CPUID information.

I would also need to know if the SX778 + SX779 have CPUID and/or SL Enhanced support.

Last edited by red-ray on 2025-04-26, 16:51. Edited 1 time in total.

Reply 2 of 2, by red-ray

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a2kkv wrote on 2025-04-26, 16:19:

It is likely that all Intel 486 SL Enhanced processors support the CPUID command.

Thank you for your reply. I had noticed all the SL Enhanced CPUs support CPUID and didn't mention it so I could see if anyone else noticed this.

I am also wondering if any Intel CPUs support CPUID that aren't SL Enhanced. SX763 is unusual as https://www.ardent-tool.com/CPU/486_Step.html says it supports CPUID, but does not specify what it returns.

It also seems that almost all the CPUs that support CPUID also support VME. Since my original post I for a SX955 and was surprised it supports PSE. If I had all models of the i486 I suspect I could figure out more edge cases, but some are rare/expensive.

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