Re: 8085 Microprocessor

From: Henning P. Schmiedehausen (hps@tanstaafl.de)
Date: Tue Apr 04 2000 - 10:41:39 EST

rob@rob.devdep.sysgo.de (Robert Kaiser) writes:

>In article <Pine.LNX.4.10.10004031337150.17213-100000@sol.compendium-tech.com>,
> kernel@blackhole.compendium-tech.com (Kelsey Hudson - kernel mailing list account) writes:
>>> FYI, a Z-80 works better. It doesn't get as hot. However, the
>>> op-codes are not compatible.
>>
>> ...which is more than obvious, as Z80 was designed by Zilog, which is not
>> Intel, and if it had compatible instructionset it would be a clone of 8085
>> and have some sort of a similar name.

>This is not at all obvious... AFAIK, the Z80 is indeed binary backward
>compatible with Intel's 8080 and 8085 parts. It was specifically designed

It is backward compatible to the 8080. Not the 8085 which had two
op-codes added (RIM (0x20) and SIM (0x30) IIRC) for setting/reading
the extended interrupt register. The Z80 had (IIRC) a relative jump
instruction as one of the opcodes.

        Ah the joy of cramming an entire OS in 2K...
                Henning 

-- 
Dipl.-Inf. (Univ.) Henning P. Schmiedehausen --             hps@tanstaafl.de
TANSTAAFL! Consulting - Unix, Internet, Security      

Hutweide 15                   Fon.: 09131 / 50654-0    "There ain't no such
D-91054 Buckenhof             Fax.: 09131 / 50654-20    thing as a free Linux"

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