On Feb 4, 2012, at 9:59 PM, Justin Richards wrote:

> A PC magazine article reviewing a new AMD processor stated " ....
> with the extra instruction sets ...".
>=20
> I think they intended to say " ...extra instructions..." and to me
> this begs a question.

Things like MMX, SSE, 3Dnow, or the FP and DSP instructions on an ARM CM4, =
are considered "extra instruction sets"; they may (probably) have their own=
 execution units that run in parallel to other instructions.


> To take advantage of these new instructions, I assume compilers used
> to compile operating systems and programs must be modified to support
> the new instructions.

Yes.  Or they could just get new libraries for existing  compilers (careful=
ly hand-written with inline assembler, or with pre-release compilers, or wh=
atever.)

> So in the short term there would be no gain using one of these
> processors with current versions of windows and linux.

Right.  And probably not with a binary distribution, either, which would pr=
obably be compiled for the most generic cpus.  (there could be run-time che=
cks for really important bits, of course.)  Thus the interest in source-bas=
ed distributions like GENTOO being expressed by SolarWind recently.


> Perhaps it turns out that the processor developers simply work closely
> with the software developers and new versions or upgrades are good to
> go at the same time as the processor is released.

It could happen.  Intel has their own compiler group, for instance.  IIRC, =
their compiler has numerous switches to control whether (and exactly which)=
 processor-specific optimizations are done.

BillW

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.