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.
--Chuck
More information about the cctech
mailing list