5 May
2025
5 May
'25
12:04 a.m.
Will Cooke wrote " although surely some people used it for normal machine code
"
Anyone without knowledge of microcode, in the sense it is being discussed here, since at
least the mid 70's would assume you were talking about code for a 6800, PIC or
whatever uP/uC.
Saying "I have just upissued the microcode" is quite a good differentiator of
folks computing knowledge.
Martin
-----Original Message-----
From: Will Cooke via cctalk [mailto:cctalk@classiccmp.org]
Sent: 04 May 2025 21:52
To: General Discussion: On-Topic and Off-Topic Posts <cctalk(a)classiccmp.org>
Cc: wrcooke(a)wrcooke.net
Subject: [cctalk] Re: Wang TTL BASIC
From all I have seen, Maurice Wilkes is considered the inventor of "microcode"
as we know it. In the linked paper from 1951 he uses the term
"micro-programme", so I think it is safe to say microcode was used in the same
way in the 70s as it is today, although surely some people used it for normal machine
code. I have seen examples of that, although none come immediately to mind.
https://www.cs.princeton.edu/courses/archive/fall09/cos375/BestWay.pdf
Will
On 05/04/2025 4:05 PM EDT Steve Lewis via cctalk
<cctalk(a)classiccmp.org> wrote:
The IBM5100 also uses the term "microcode" - but I'm not sure if that
term
pre-1975 means the same as what, say, Intel used it for around the x86?
I've seen a glimpse into the syntax of the x86 microcode. In the IBM
5100's case, its CPU is distributed across 14 or so SLT chips - so I never
fully understood how it implements its PALM instruction set. I know the
two large IC on that process are two 64-byte memory things (dunno if
categorized as SRAM or DRAM, or neither), mapped to the first 128
bytes of system RAM (so a high speed pass through, where that 128
bytes correspond to the registers used by each of the 4 interrupt
levels). That PALM processor was developed right around the time of
the Intel 4004 (late '71 / mid '72), and stout enough to run a version
of APL about a year later (I see Intel made a version of FORTRAN for
the 8008, or at least a claim for it in the Intertec brochures).
Anyway, all I mean is, in early 70s did "microcode" just mean
instruction-set, and that changed a few years later? Or did microcode
always mean some kind of "more primitive sequence" used to construct
into an instruction set?
-Steve
On Sun, May 4, 2025 at 1:33 PM ben via cctalk <cctalk(a)classiccmp.org> wrote:
> On 2025-05-04 2:11 a.m., jos via cctalk wrote:
> >> I recall that system had many boards, the whole "CPU" box was
> >> external
> to
> >> the monitor (and in the earliest versions, the power supply was also a
> >> large external box). I can't really fathom creating a BASIC out of
raw
> >> TTL, or maybe I'm misunderstanding the approach.
> > You build a processor with some TTL, and then implement a BASIC on
> > that microprocessor.
> > There is always this intermediate step, no machine executes BASIC
> > directly in TTL.
> >
> Well for BASIC that is true.
> The Fairchild Symbol Computer was test to just how far TTL could go.
>
> > Look here for an example of a processor (Datapoint 2200) in TTL :
> >
> >
> https://bitsavers.org/pdf/datapoint/2200/jdreesen_shematics/DP2200_m
> b.pdf
> >
> > Jos
> Micocoded coded machines, could likely be programed to run basic.
>
> Ben.
>
>
You just can't beat the person who never gives up.
Babe Ruth