Geode instruction set

see Hardware specification and AMD's Geode GX data book

The Geode's instruction set is a mix of several instruction sets. As per data book (2.1 - CPU Core, pg.15):

General

Generally speaking, the Geode GX is a combination the following instruction sets:

• Intel's Pentium(r)
• AMD-K6(r)
• Athlon(tm) FPU
• AMD Geode Castle

Specific Instruction Sets

In particular (and from AMD's documentation) it supports the following instruction sets:

• Pentium
• Pentium Pro
• 3DNow! (AMD-K6 and Athlon processors)
• MMX (Athlon processors)
• subset of Geode Castle (including special SMM instructions)

• does not support SSE, except for the subset supported in Athlon's 3DNow! Enhanced.
• does support MMX for Athlon (itself a subset of Pentium 3 KNI)