Re: port-xen/53267 (XEN amd64 DomU (Dom0??) NetBSD current USERMODE() fails)

[John Nemeth <jnemeth%cue.bc.ca@localhost>]

The following reply was made to PR port-xen/53267; it has been noted by GNATS.

From: John Nemeth <jnemeth%cue.bc.ca@localhost>
To: Robert Elz <kre%munnari.OZ.AU@localhost>, John Nemeth <jnemeth%cue.bc.ca@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: port-xen/53267 (XEN amd64 DomU (Dom0??) NetBSD current USERMODE() fails)
Date: Sun, 13 May 2018 13:22:35 -0700

 On May 13, 11:57pm, Robert Elz wrote:
 } 
 } Thanks for taking the trouble to explain all of that.
 } 
 } In particular:
 } 
 }   |      AMD noted that rings 1 and 2 weren't used much and dumped them
 }   | as unused legacy stuff. 
 } 
 } which explains a lot - I had wondered why they were not used.
 } 
 } ps: I still think the 8080 was the worst of the competing 8 bit processors
 } of the time, and while I applaud Intel's capacity to extend it while more
 } or less keeping complete compat with ancient code, I really wish that IBM
 } had selected one of the other choices...
 
      Both the 8088 and 68000 came out in 1979.  The IBM PC came
 out in 1981.  It certainly would have been nicer if IBM had chosen
 the 68000.  Being a 32-bit processor with a large register set from
 the get-go (albeit with a 16-bit bus), it was definitely far superior
 tecnologically.  One could argue that in many ways, it is still
 superior.  However, having been abandoned for the most part, it
 doesn't have a 64-bit upgrade path, nor would it have the same
 performance of modern x86 processors.  Unfortunately, technological
 superiority is not the only consideration in making design choices.
 
 }-- End of excerpt from Robert Elz