My understanding is it IS a full x86 instruction set. ie these x86 instructions:
The question is open how many of the x87 instructions survived (FP math). Probably not many
. According to the P54C datasheet, all x87 instructions are included.
However, is it WITHOUT
MMX, MMX+, 3DNOW, SSE, SSE2, SSE3, SSE4
ref: P54C was prior to P55, which introduced MMX. P54C was basically the first pentiums: ftp://download.intel.com/design/pent...s/24199710.pdf
In place of MMX, etc, is a new set of SIMD instructions which, as w1zz alluded to, are mostly MUL + ADD (and other instructions) that operate on "vector data", ie not 32-bits, but 128bits or more at the same time. The chosen instructions are designed to fit the purpose of what a GPU does.My guess is that Larrabee will implement some MASSIVE vectors, e.g. 512bit or 1024 bits. Or it will operate on column matrices (multiple vectors simultaneously), to process a whole bunch of "coloured" pixels simultaneously.
HOWEVER, I do think there will be some additional stuff in there: Intel is NOT just building a GPU here... they are building a general purpose "transputer" that is designed to render CUDA etc. irrelevant.