Re: Apple, Jobs, and the irony of it

[Eric Smith <eric-no-spam-for-me@brouhaha.com>]

mjmahon@aol.com (Michael J. Mahon) writes:
> There is a certain irony here, in that both AMD and Intel
> implementations of the IA-32 architecture, in their current
> 32-bit chips, do not run the IA-32 instructions "as written".

Huh?  There have been processors for more than forty years that have not
been hardwired to execute the documented user-level instruction set.
The microarchitectures have gotten a lot more complex over those forty
years [*], but I don't think it's fair to claim that a Pentium Pro/2/3/4
or Athlon doesn't execute IA-32 instructions "as written".  If AMD,
Intel, Nexgen, and Transmeta hadn't bragged about how clever their
microarchitectures are, you wouldn't even be thinking about making such
a statement.

The fact is that these chips DO execute IA-32 instructions "as written".
The way they execute them just happens to be very complex.

Eric



[*] It took until the 1990s for microprocessors to catch up with the
implementation techniques IBM invented in the 1950s and 1960s with
machines like Stretch (7030) and the 360/91, such as speculative
execution and register renaming.  So complex microarchitectures are
actually nothing new.