sergey
Veteran Member
... NEC V40/V50 chips. One interesting feature is that these chips had extra lines to tell you what segment (CS, DS, ES, SS) a memory reference was using, so you could conceivably hang 4MB of memory on one.
Actually you can do the same with 8086/88 (but apparently not with 80188/186). 8086 and 8088 have S3-S4 status signals that are multiplexed with A16 and A17 address signals, that specify which segment is used for addressing. But it would be a kludge to use it for extending memory to 4MB using this feature. Using some kind of paging is more useful (LIM EMS?!).
BTW - POP CS works on all 8088, 80C88, and NEC V20. And I assume will work on 8086/V30 as well.
Thanks,
Sergey