On 14 Dec 2023 at 21:52:06, Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:

On 2023-12-13, Peter Flass <peter_flass@yahoo.com> wrote:

Ahem A Rivet's Shot <steveo@eircom.net> wrote:

On Wed, 13 Dec 2023 03:31:08 -0000 (UTC)
John Levine <johnl@taugh.com> wrote:

A big difference between the computing world now and back in the 1960s >>>> and 1870s when people were designing segmented machines is that then
the important software was written in machine-specific assembler,
while now it's all in C or other languages which don't really care
about the underlying instruction set, although C and its decendants
have assumptions about byte addressed flat memory baked deep into them. >>>

C for the 286 was a horror story with multiple memory models and
near and far pointers exposed in the source code.

When I first started looking at the architecture, I thought all the memory >> models were just nuts.

Yeah, too bad the Motorola 68000 arrived just a bit too late.

I liked the Texas 9900 instruction set.


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On Fri, 15 Dec 2023 07:22:33 +0000, Bob Martin wrote:

On 14 Dec 2023 at 21:52:06, Charlie Gibbs <cgibbs@kltpzyxm.invalid>
wrote:

On 2023-12-13, Peter Flass <peter_flass@yahoo.com> wrote:

Ahem A Rivet's Shot <steveo@eircom.net> wrote:

On Wed, 13 Dec 2023 03:31:08 -0000 (UTC)
John Levine <johnl@taugh.com> wrote:

A big difference between the computing world now and back in the
1960s and 1870s when people were designing segmented machines is
that then the important software was written in machine-specific
assembler, while now it's all in C or other languages which don't
really care about the underlying instruction set, although C and its >>>>> decendants have assumptions about byte addressed flat memory baked
deep into them.

C for the 286 was a horror story with multiple memory models and
near and far pointers exposed in the source code.

When I first started looking at the architecture, I thought all the
memory models were just nuts.

Yeah, too bad the Motorola 68000 arrived just a bit too late.

I liked the Texas 9900 instruction set.

My favourite is the ICL 2900 instruction set - loosely based on the
Manchester MU5. Great for compiler writers.

http://www.ancientgeek.org.uk/ICL/The_ICL_2900_Series.pdf




--
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
http://www.mirrorservice.org

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On 15 Dec 2023 07:22:33 GMT
Bob Martin <bob.martin@excite.com> wrote:

I liked the Texas 9900 instruction set.

Yes it was nice - the chip itself somewhat less so.

There was a 9900 based machine being built by a fellow student when
I was at college. The board was built, the wiring tested, all the other components were in their sockets the time had come to put that 0.9" wide
sixty four pin ceramic packaged processor into its socket - many members of
the university processor group (student club) were present to watch ...

It really did not want to go in - not because the legs were splayed,
it was a ceramic package with straight legs. Instead it provided an object lesson in the meaning of the term insertion force. In the end padded
support went under the board while the precious processor was tapped into
its socket with the aid of a small rubber mallet.

I stopped wanting to build one.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/
Host: Beautiful Theory meet Inconvenient Fact
Obit: Beautiful Theory died today of factual inconsistency

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Reply-To: slp53@pacbell.net

Bob Martin <bob.martin@excite.com> writes:

On 14 Dec 2023 at 21:52:06, Charlie Gibbs <cgibbs@kltpzyxm.invalid> wrote:

On 2023-12-13, Peter Flass <peter_flass@yahoo.com> wrote:

Ahem A Rivet's Shot <steveo@eircom.net> wrote:

On Wed, 13 Dec 2023 03:31:08 -0000 (UTC)
John Levine <johnl@taugh.com> wrote:

A big difference between the computing world now and back in the 1960s >>>>> and 1870s when people were designing segmented machines is that then >>>>> the important software was written in machine-specific assembler,
while now it's all in C or other languages which don't really care
about the underlying instruction set, although C and its decendants
have assumptions about byte addressed flat memory baked deep into them. >>>>

C for the 286 was a horror story with multiple memory models and
near and far pointers exposed in the source code.

When I first started looking at the architecture, I thought all the memory >>> models were just nuts.

Yeah, too bad the Motorola 68000 arrived just a bit too late.

I liked the Texas 9900 instruction set.

The Burroughs medium systems instruction set was a joy to
work with. It was BCD, so one never needed to convert
between decimal and hex, or decimal and octal.

The instruction set basically mapped 1-1 to COBOL verbs.

COMPUTE HQ1 = (B - 1) / 14 + 1. 526 CARD 1 65428
01 065428 MVN 11A103 100000 100336 CODE
01 065446 MVN 110303 217556 100340 CODE
01 065464 DEC 030303 100336 100340 CODE
01 065482 MVN 110306 100340 100344 CODE
01 065500 MVN 11A115 000000 000351 CODE
01 065518 MVN 11A119 000000 100366 CODE
01 065536 DIV 06A221 140000 100344 100366 CODE
01 065560 MVN 11A105 100000 100386 CODE
01 065578 MVN 11A115 000000 000392 CODE
01 065596 INC 011920 100366 100386 CODE
01 065614 MVN 110101 000391 217452 CODE

INSPECT COURSE-B REPLACING ALL " " BY ZEROS. 531 CARD 1 65864
01 065864 MVN 110607 000774 100008 CODE
01 065882 SEA 39B101 400000 600000 050384 CODE
01 065906 NEQ 25 0C065962 CODE
01 065916 MVA 10A202 F0F0F0 400000 CODE
01 065934 INC 01A107 200000 100008 CODE
01 065952 BUN 27 0C065882 CODE

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On 15/12/2023 09:18, Bob Eager wrote:

My favourite is the ICL 2900 instruction set - loosely based on the Manchester MU5. Great for compiler writers.

That's the first machine I used professionally. I quite liked the
DECsystem10 we had at Uni.

I went from the 2900 to an Intel 8085. Yuck. I spent quite a lot of my
career with 8085/8086/286 (yes, occasionally in protected mode), 386...
- and I never liked any of them.

More recently I used ARM chips, and TBH I don't really know what they
are like. I never needed to, they are fast enough without needing assembler.

Andy

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On Fri, 15 Dec 2023 21:22:57 +0000, Vir Campestris wrote:

On 15/12/2023 09:18, Bob Eager wrote:

My favourite is the ICL 2900 instruction set - loosely based on the
Manchester MU5. Great for compiler writers.

That's the first machine I used professionally. I quite liked the
DECsystem10 we had at Uni.

I used a PDP-10 (it was an old KA-10, and was never known as a
DECsystem-10) for a year. Hoping to build a replica soon.

I went from the 2900 to an Intel 8085. Yuck. I spent quite a lot of my
career with 8085/8086/286 (yes, occasionally in protected mode), 386...
- and I never liked any of them.

My next was a Z80, then VAX, then 8086. I'd done PDP-11 long before.

More recently I used ARM chips, and TBH I don't really know what they
are like. I never needed to, they are fast enough without needing
assembler.

I only really looked at instruction sets in the context of writing
compilers.



--
Using UNIX since v6 (1975)...

Use the BIG mirror service in the UK:
http://www.mirrorservice.org

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