VT101 8085 CPU Fault

Chuck Guzis cclist at sydex.com
Sun Jan 18 20:43:32 CST 2015

On 01/18/2015 05:28 PM, Mouse wrote:

> I'm probably just exposing my ignorance of the 8085 here, but did it
> have anything like the prefix opcodes x86 has (repne et al)?  I'm
> wondering if it could be stuck doing something like (to admittedly try
> to use syntax I don't really know) "repne cmp %ax,%ax" that would never
> occur normally but might compute forever without fetching anything
> further.  Or, does it have a instruction prefetch buffer?  (My guess
> would be it's too old for that, but I don't really know.)  If so, a
> very tight loop might execute entirely out of the prefetch buffer....

None of that.  Think of it as an 8080 with a few extra instructions, a 
bit-bang serial I/O facility, and some extra vectored interrupt lines 
and a TRAP interrupt--and +5 volt operation.  Really, not even as 
complex as a Z80.


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