Re: OoO execution (was: The Seymour Cray Era of Supercomputers)

On Mon, 19 May 2025 06:22:42 GMT
anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:

 
The innovation that made OoO execution generally usable rather than a
publicity stunt like the 360/91 is the reorder buffer (ROB), which
allows to retire the instructions in-order, and to cancel
speculatively "executed" instructions after an exception or branch
misprediction.
 
The Pentium Pro (introduced 1995-11-01), HP PA-8000 (introduced
1995-11-02), and MIPS R10000 (introduced 1996-01) are the first
microprocessors which have full-blown OoO execution.
 

What about PPC604? It had more limited OoO resources than the 3
processors you mentioned above, esp. fewer numeber of reservation
stations, but it most certainly had reorder buffers, 16 of them.
So, by your own definitions, it should be called the first single-chip
full-blown CPU.