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From: ching@brahms.amd.com (Mike Ching)
Newsgroups: comp.arch
Subject: Re: ---486 compatibility with 8008
Message-ID: <1990Nov9.164838.26423@amd.com>
Date: 9 Nov 90 16:48:38 GMT
References: <1990Nov4.014901.23819@zoo.toronto.edu> <1990Nov6.223738.13265@ux1.cso.uiuc.edu> <9333@b11.ingr.com>
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Organization: Advanced Micro Devices; Sunnyvale, CA
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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.
>
...
>
>Larry (in shaky voice: "When I was a lad - we barely had 64K bytes of
>memory, and were GRATEFUL for it".... cough cough) Hughes
> 

Weren't the Zilog mnemonics a result of Intel copyrighting theirs? Ones
already in use like CALL and PUSH could be used by Zilog but the "new"
ones like MOV and ANA were copyrighted. Which leads to absurdities like
Zilog putting a trademark on the letter Z.

Mike Ching