Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!apple!metaphor!neuromancer!djh
From: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Newsgroups: comp.arch
Subject: Re: Zilog's mnemonics; a boon to programmers
Message-ID: <1768@metaphor.Metaphor.COM>
Date: 12 Nov 90 20:14:04 GMT
References: <1990Nov4.014901.23819@zoo.toronto.edu> <1990Nov6.223738.13265@ux1.cso.uiuc.edu> <9333@b11.ingr.com> <1990Nov9.164838.26423@amd.com>
Sender: news@metaphor.Metaphor.COM
Reply-To: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 41

In article <1990Nov9.164838.26423@amd.com> ching@brahms.amd.com (Mike Ching) writes:
>In article <9333@b11.ingr.com> lhughes@b11.ingr.com (Lawrence Hughes) writes:
>...
>>
>>The Z80 WAS upward compatible with the 8080, at both architecture and binary
>>opcode level - curiously enough, though, the bright boys at Zilog invented
>>a better (read "different and incompatible") symbolic assembly langauge
>>which made it much more difficult to take advantage of the Z80's extended
>>instructions: you either stuck with Intel mnemonics (and the 8080 subset) or
>>worked with Zilog's "preverted" ones (e.g. almost half the actual binary 
>>opcodes mapped onto the single symbolic opcode "LD"). Zilog's symbolic
>>language was SUCH a turkey, that several extended Intel symbolic assembly 
>>languages were developed (and widely used) leading to a regular tower of Babel.
>>Clever, Zilog.

Ahem, excuse me, but Zilog's mnemonics were readable and orthogonal in a way
that Intel's never were, and were by far the more popular standard for Z-80
programming. Intel was never quite sure how to recast the Z-80 extended ops
into their particular mold; often their syntax was just borrowed "as is"
from the TDL Zilog format. Unless you had a vested interest in the 8080 for
some reason, Zilog mnemonics were simply the preferred way to go. It's
interesting to note that Zilog was founded by ex-Intelites.

On the binary opcode level, the Z80's instructions were mondo hack attempts
to extend the language while maintaining almost complete backward
compatibility with the 8080. Simple conversion programs have always been
available to translate between different formats, so I don't see any reason
to get religious over this issue. Frankly, this is the first time I've
ever heard ANYONE get religious over Intel's (!@#?!) assembler syntax.

Now Motorola, there's a company that really did things right...

LDIR! CPIR! EXX! Reasons to Live!
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| Dallas J. Hodgson               |     "This here's the wattle,             |
| Metaphor Computer Systems       |      It's the emblem of our land.        |
| Mountain View, Ca.              |      You can put it in a bottle,         |
| USENET : djh@metaphor.com       |      You can hold it in your hand."      |
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