CPUID.md

Notes on CPU compatibility

List of the required features. Note: wide support/AMD64 means both AMD and Intel.

Greentea OS targets CPUs at least from 2012 (Q3 2011 and newer)

• UEFI is common since late 2011
• SSE2 is mandatory on AMD64
• NX bit should be present on all AMD64
• SSE3 wide support since 2005
• CMPXCHG16B wide support since 2006
• PrefetchW wide support since 2006
• LAHF/SAHF wide support since 2005
• POPCNT wide support since 2008
• 2 MB huge pages seems to be mandatory on AMD64
• I/O APIC mandatory on multi-core AMD64
• ACPI 2.0 required by Tofita
• SSE4.1 wide support since 2011 (CPU with SSE4.1 will have SSE3 and SSSE3)
• SSSE3 wide support since 2011
• SSE4.2 wide support since 2011

Virtual machine (like VT-x) extensions may become required in the future.

Emulated features:

• Greentea is supposed to emulate AVX and other features on the older CPUs to allow unsupported apps to run

Optional features:

• 1 GB huge pages (aka PDPE1GB) wide support since 2012 and used as optimization
  • May be not present on virtual machines
• x2APIC is optional on AMD and used by Greentea if present

Not required features:

Not used by Greentea system itself but available for third-party apps.

• SSE4a seems like AMD-only
• AVX wide support since 2011 (except Atom, some modern Pentium & Celeron, old Xeon)
• AVX2 introduced in 2013
• AVX-512 introduced in 2016