I try to understand what stays and goes. I read this:<p><a href="https://www.intel.com/content/www/us/en/developer/articles/technical/envisioning-future-simplified-architecture.html" rel="nofollow">https://www.intel.com/content/www/us/en/developer/articles/t...</a><p>So all 16 bit goes away. 32 bit is still possible, but only in user mode. The OS is always 64bit. 32bit style segmentation goes. Insb/outsb goes.<p>This doesn't seem so bad. 16 bit is almost always in emulators anyway. 32 bit user code can stay. Presumably OS page table magic can hide segment registers missing. We need to upgrade the OS, but user mode won't take much of a hit.<p>I wonder how much they gain in practice. Probably a huge simplification in speed critical address calculation.<p>Can't see them gain much by dropping ins/outs, but they probably won't be missed much anyway.<p>I notice A20 already went away in 2008. Never noticed it go, it only caused misery.
FWIW I tried to explain the background and context, including the now-forgotten 80376 CPU, when this was proposed last May.<p><a href="https://www.theregister.com/2023/05/25/intel_proposes_dropping_16_bit_mode/" rel="nofollow">https://www.theregister.com/2023/05/25/intel_proposes_droppi...</a><p>Yes. 80376, not 80386. Not a typo.