[TUHS] 68k prototypes & microcode

[Dave Horsfall]

On Wed, 3 Feb 2021, Larry McVoy wrote:

>> The 68K always reminded me of the VAX.
>
> I'm not sure if that is a compliment or not.

The 68K was fairly clean; the VAX not so much...  I got the impression
that it was designed by a committee i.e. everybody wanted to have their
own instruction/feature, and it showed.  I do admit though that paging the
page tables was a stroke of genius.

> The NS320XX always reminded me more of the PDP-11 (which is by *far*
> my favorite assembler, so uniform, I had a TA that could read the octal
> dump of a PDP-11 like it was C).  I wasn't that good but I could sort of
> see what he was seeing and I never saw that in the VAX.  68K was closer
> but I felt like the NS320xx was closer yet.  Pity they couldn't produce
> bug free chips.

I used to be a whiz on the 360 :-)  As part of our final CompSci exams
we had to hand-assemble and disassemble some code, and I hardly ever referred
to the "green card".

> Someone mentioned Z80000, I stopped at Z80 so I don't know if that was
> also a pleasant ISA.

The Z80 was quite nice; I wrote heaps of programs for it, and I even found 
an ANSI C Compiler for it (Hi-Tech as I recall; BDS-C was, well, you could 
barely call it "C")[*].  I compiled a number of Unix programs...

> The x86 stuff is about as far away from PDP-11 as you can get.  Required
> to know it, but so unpleasant.

The x86 architecture is utterly brain-dead; I mean, what's wrong with a
linear address space?  I think it was JohnG who said "segment registers
are for worms".

> I have to admit that I haven't looked at ARM assembler, the M1 is making
> me rethink that.  Anyone have an opinion on where ARM lies in the pleasant
> to unpleasant scale?

I've been looking at the ARM; it seems quite nice at first glance.

> --lm who misses comp.arch back when CPU people hung out there

Indeed.  I gave up on USENET when the joint got flooded by spammers; I 
still have my "cancel" script somewhere.

[*]
I think it was Henry Spencer who said (in an unrelated matter): "Somehow 
to be called a C compiler, I think it ought at least be able to compile 
C".

-- Dave, who ran aus.radio.amateur.*