> On Sep 29, 2026, at 3:44 PM, ben via cctalk <[email protected]> wrote:
>
> On 2026-09-29 11:36 a.m., Paul Koning via cctalk wrote:
>>> On Sep 29, 2026, at 1:22 PM, ben via cctalk <[email protected]> wrote:
>>>
>>> ... Like what machines other than IBM had binary and decimal computing?
>> That depends. One answer is "all of them" -- because any general purpose
>> computer can do both.
>
> True, but in 60's and 70's only PL/1 or subsets of it could do binary and
> decimal computing in a high level language.I have not looked at any newer
> languages cause nothing would ever port.
Um, you forgot COBOL! Which is still around; GCC now includes a COBOL
compiler. RPG maybe also, though I don't know that language. And nowadays
there is Python, though I don't know if the decimal arithmetic library on
Python/VAX would use those instructions.
>> If you meant "had machine instructions both for decimal and for binary
>> arithmetic", the answer includes the PDP-11 and VAX, and I think the Intel
>> 4004 had instructions used as building blocks in decimal arithmetic.
>
> You must of had a custom PDP 11 then.
Nope. It's the "commercial instruction set" which was an optional feature on
several PDP-11 models sold by DEC, clearly documented in the PDP-11
architecture manual, and supported by at least COBOL and probably RPG; the
kernel would also use the CIS MOVC instruction for memcpy if present in the
machine. There is of course the famous PDP-11/74 (one of two unshipped models
of that name) which was an 11/70 with CIS added, canceled around the time the
VAX came out. Internal rumors were that it was due to it being faster than the
VAX for COBOL workloads.
paul
