barrett@hp-dcde.UUCP (01/19/84)
#N:hp-dcde:30900001:000:849 hp-dcde!barrett Jan 17 17:51:00 1984 Well, this is one of the most silent newsgroups I have ever seen considering the power of the 16000 archetecture. I would expect to see a flurry of activity. I have a couple of simple questions. Does anyone out there have any ideas as to why the MOD register is only 16 bits wide? This poses some annoying problems when you want to put ROMS in the low part of the address space (as you might be inclined to do since the power-up state of the PC is 0). Secondly, I would like to get a hold of a 16000 deveklopment board and a portable X-compiler for a BELL III UNIX system. Is it too soon to be able to get them at a reasonable price? If not, anyone have any ideas on who I can talk to since I'm not currently associated with a university. Dave Barrett (hplabs!hp-dcd!barrett) (303) 226-3800 x2271 Fort Collins, CO. 80525
eich@uiuccsb.UUCP (01/21/84)
#R:hp-dcde:30900001:uiuccsb:4500003:000:422
uiuccsb!eich Jan 21 00:55:00 1984
I don't know why MOD was made 16 bits (maybe just to save space, both
on the chip and on the stack whenever CXP{D} or an interrupt is
handled?). But with the MMU, the OS can map ROMs which lie in low
physical memory anywhere you like anyway. Or lacking the MMU (which
doesn't translate addresses after reset until programmed), why not just
overlay ROM while booting, then disable it?
Brendan Eich
uiucdcs!uiuccsb!eich