Re: AMD (fwd)

Craig Milo Rogers (rogers@isi.edu)
Sat, 21 Dec 96 22:18:11 PST

>: 1) No. AMD5x86 only has 486 instructions. Pentium has Pentium
>: instructions.
...
>I'd say that this response does absolutely nothing to clarify things.
>Sure, a Pentium is a Pentium, and an AMD5x86 is not. Thanks for
>pointing that out to us. Now, as far as I know, there are no user
>level instructions in the Pentium that are not found in the 486.

I've excerpted and amplified the relevant text from the
Pentium(R) Processor Family Developer's Manual, Volume 3: Architecture
and Programming Manual, a PDF file downloadable from:

http://developer.intel.com/design/pentium/manuals/pent4.htm

Section 23.2.7.1: NEW PENTIUM PROCESSOR INSTRUCTIONS

The Pentium Processor introduces three new application instructions:

* CMPXCHG8B instruction

Compare and exchange 8 bytes

* CPUID instruction

Get CPU identification information

* RDTSC instruction

Read the timestamp counter

For comparison, from section 23.2.7.2 of the same document,
the 486 added three application-level instructions beyond the 386's
repetoir:

* BSWAP instruction

* XADD instruction

* CMPXCHG instruction

Craig Milo Rogers