Re: Computer architects leaving Intel...

In article <vaqgtl$3526$1@dont-email.me>, cr88192@gmail.com (BGB) wrote:

On 8/29/2024 11:23 AM, MitchAlsup1 wrote:

With differing instructions, how does a software vendor write
software such that it can run near optimally on any implementation?

 
They presumably target whatever is common, or the least common
denominator (such as RV64G or RV64GC), and settle with "probably
good enough"...

ISVs can be proactive or passive about adopting a new ISA. Anyone
promoting a new ISA wants to motivate them to be proactive, but faces
problems with prerequisites:

* Who can work with simulators, and who needs hardware?
* Different kinds of software need more or less powerful hardware.
* Application people need an OS and development tools at minimum.
* Quite often they need other software: math libraries, databases, etc.

But, probably not too much different from other ISAs, just with a
lot more parties involved.

Variant ISAs create fear, uncertainty and doubt, and that means delay.
ISA promotors fear delay, because their investors will run out of
patience.

The alternative is that one expects that all the software be
rebuilt for the specific configuration being used,

ISVs /really/ don't like that. It multiplies their testing and QA and
those are expensive. It rarely shows up problems, but convincing
themselves to do without it is hard for them.

or recompiled from source or some other distribution format on
the local machine which it is to be run (with binaries distributed
as some form of "portable IR").

ISVs get sceptical about that, because it's generating code they have not
tested.

John