[TUHS] 68k prototypes & microcode
Dave Horsfall
dave at horsfall.org
Fri Feb 5 07:55:19 AEST 2021
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.*
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