gallier2 (gallier2.delete@this.gmx.de) on August 5, 2014 1:28 am wrote:
> Maxwell (max.delete@this.a.com) on August 4, 2014 7:55 pm wrote:
> > Obviously a typo, he meant 8080. Although the 8086 wasn't binary compatible with the 8080, you could
> > convert 8080 assembly source code to 8086 with a simple translator (not that anyone did).
>
> NEC's V20/V30 were binary compatible with 8080 and with 80186. They had a special trap instruction that put
> the CPU in 8 bit mode. There was also an instruction to get back in 16 bit mode. The segment registers were
> set before going in emulation mode. This would allow something like multiple virtual 8 bit machines. I don't
> know if it was used that way anywhere but it's fascinating to see what was possible at a time.

I never saw this capability used to run 8080 code virtually but did heard about systems intended to boot MS-DOS, CP/M-86, and CP/M with the same hardware.