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Message
From: Jecel Assumpcao Jr<jecel@m...>
Date: Mon Sep 24 18:21:50 CEST 2007
Subject: [oc] Assembler Compatible But Not Binary Compatible
"big one" wrote on Sun, 23 Sep 2007 20:05:16 -0700> I read that Zilog Z-80 is assembler compatible but not binary compatible
> with Intel 8080. The new CPU have the same number and type of
> registers and ALU.
The Z80 was binary compatible with the 8080 (but with many new
instructions). Unfortunately, Intel had copyrighted its set of mnemonics
so the Zilog guys had to create a different set for their own assembler.
This turned out to be much nicer than Intel's.
It was lucky that software patents were not possible back then and even
copyright for binary code (instead of source code) was still being
debated or the story might have been very different.
One case where a processor had the same assembler but different binary
codes was the 6809. Since this was compatible with Motorola's own 6800
there was no danger of any legal trouble (contrast that with the pin
compatible 6501 from MOS Technology). The 8086 was mostly compatible
with the 8008 at the assembly level, but since both were from Intel
there were no problems here either.
> Is there any core project on OpenCores with "Assembler Compatible, but
> not binary compatible" with major CPU architectures, such as x86, ARM,
> MIPS, etc?
>
> If not, is it possible to start a new project?
The assembler of our times is C, so I don't see the value of such a
project.
-- Jecel
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