Petz,
On 64 bit extension:
In terms of SSE(x) to do 64 bit integer arithmetics, it is a little kludgy. SSE resides in FPU, and has no communication with normal registers. It communicates only with 64 or 128 bit MMX registers or memory. You can't do branching based on it, and in general the operations on MMX registers are limited. Generally, an architecture is considered say 32 or 64 bit based on the size of the normal integer register. So the SSE is a non-starter on many fronts.
So you really need to redo the ALU and switch to 64 bit integer registers - which may brake a lot of code, and without 64 bit addressing, it is still not a full 64 bit architecture, and in general, if Intel is going to bite the bullet and do an x86 extension, I don't see any reason to do an half assed job, that you are suggesting they will do.
The reason is that to this day, Intel is not sure about Itanium. It is plan A, and there is no plan B. A half assed 64 bit extended x86 is still no plan B. So if plan A fails, Intel doesn't have a plan B, and would still need to come up with a completely new plan B to be a longer term solution.
Joe |
