On 2021-07-07 16:12, Hans Rosenfeld wrote:
On Wed, Jul 07, 2021 at 03:51:47PM +0200, Johnny Billquist wrote:But I still sortof fail understanding why something like the Ragge FPGA VAX would be interesting to have PDP-11 emulation on. Like I said, I seriously doubt it would be capable of running early VMS for multiple other reasons. And the PDP-11 mode in the VAX have limitations that makes it much less attractive than any normal PDP-11.Well, wouldn't it be awesome if NetBSD/vax64 can run 2.11BSD binaries natively?
I think you are underestimating the limitations of the PDP-11 compatibility mode of the VAX...
No split I/D space, no FP, any kind of trap exits out to VAX mode, anything that depends how the memory management of the PDP-11 works will have issues... Even some instructions you might play with are missing (but I don't think most people would miss them, especially not since we don't have split I/D space anyway).
Very few 2.11BSD programs would work in this environment... The most serious limitation is the lack of split I/D space.
Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt%softjar.se@localhost || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol