[Info-vax] System Programming versus Application Programming

[John Reagan]

On Saturday, February 8, 2014 1:27:23 PM UTC-5, JF Mezei wrote:

> 
> But when Intel comes out with a new 8086, does it require the same type
> of OS tuning as did the transition from Tukwila to Poulson ?
> 
> 
> Or is upward compatibility too important in the x86 market and new chips
> will run "off the shelf" opetating systems without any tailoring being
> required ?
> 

Tuning?  Probably not for most applications or OS.  However, yes, each chip seems to have a ton of chip-specific registers.

Check out

http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html

and look at volume 3, chapter 34 (Model-specific registers).  You'll also find manuals on optimizing for current chips and other manual on upcoming chips and upcoming instructions.

While you can easily write code that runs on all of them, you also have a ton of chip specific registers and chip specific optimal code sequences.