PDP-12 at the RICM

Fred Cisin cisin at xenosoft.com
Tue Jul 14 23:22:24 CDT 2015

>  The 8086 had four segment registers:
> 	CS	- Code segment, used with IP register
> 	DS	- Data segment
> 	SS	- Stack segment, used with SP and BP registers
> 	ES	- Extra segment, used with DI for string instructions as
> 		  destination (DS:SI as source)
>  You could override instructions dealing with memory with any of the
> segment registers:

If you were writing an emulator, what would you have it do if an interrupt 
occurred while in a REP operation with a segment override?

Just how accurately should an emulator match the behavior of the emulated 

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