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From: =?UTF-8?B?U2lndXLDsHVyIMOBc2dlaXJzc29u?= <siggi@sort.is>
Date: Tue, 26 Aug 2025 09:45:17 -0400
Message-ID: <CACtr8n1pgt+J7LSu7xL9Ehf9demxNbiB==YtyLMAzV0t3t-nTg@mail.gmail.com>
Subject: Ghidra disassembler for SC/MP
To: 052922@sbc-85.com
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Hey there,

I saw your videos about the Nibbler, and it piqued my curiosity about the
SC/MP processor. The instruction and register sets are pretty unique to my
eye, though in a way much better put together than the initial MC6800
instruction set
<https://sigurasg.github.io/reversing-the-2465/2024/06/18/mc6800-limitations.html>.
The SC/MP will have no problem with reentrant programming and it should be
relatively easy to e.g. write a C compiler for it.

In any case, to understand the processor better, I wrote a Ghidra/Sleigh
language spec <https://github.com/sigurasg/GhidraSCMP> for it. This is very
early stage code, but the spec does seem to disassemble SC/MP code without
issue.
As I haven't implemented the semantics for most of the instructions, the
Ghidra decompiler is still pretty useless. I'm not sure how good it will
ever do, as the SC/MP instruction set is somewhat unorthodox. My
GhidraMC6800 language spec does quite well with the MC6800, so perhaps
Ghidra will figure it out...

Is there some kind of forum or mailing list you know of where SC/MP nerds
who might appreciate this and/or might be willing to help hang out?

Siggi

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<div dir=3D"ltr">Hey there,<div><br></div><div>I saw your videos about the =
Nibbler, and it piqued my curiosity about the SC/MP processor. The instruct=
ion and register sets are pretty unique to my eye, though in a way much bet=
ter put together than the <a href=3D"https://sigurasg.github.io/reversing-t=
he-2465/2024/06/18/mc6800-limitations.html">initial MC6800 instruction set<=
/a>. The SC/MP will have no problem with reentrant programming and it shoul=
d be relatively easy to e.g. write a C compiler for it.</div><div>=C2=A0=C2=
=A0</div><div>In any case, to understand the processor better, I wrote a <a=
 href=3D"https://github.com/sigurasg/GhidraSCMP">Ghidra/Sleigh language spe=
c</a> for it. This is very early stage code, but the spec does seem to disa=
ssemble SC/MP code without issue.</div><div>As I haven&#39;t implemented th=
e semantics for most of the instructions, the Ghidra decompiler is still pr=
etty useless. I&#39;m not sure how good it will ever do, as the SC/MP instr=
uction set is somewhat unorthodox. My GhidraMC6800 language spec does quite=
 well with the MC6800, so perhaps Ghidra will figure it out...</div><div><b=
r></div><div>Is there some kind of forum or mailing list you know of where =
SC/MP nerds who might appreciate this and/or might be willing to help hang =
out?</div><div><br></div><div>Siggi</div></div>

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