On 2020-08-09 15:05, Seymour J Metz wrote:
How is the ASCII bit relevant to teletypes? It only affects the
handling of the sign nybble.
You might want to check out the UNPK instruction.
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
________________________________________
From: IBM Mainframe Assembler List <[email protected]>
on behalf of Robin Vowels <[email protected]>
Sent: Saturday, August 8, 2020 11:40 PM
To: [email protected]
Subject: Re: Case Study: IBM SYSTEM/360-370 ARCHITECTURE (1987)
----- Original Message -----
From: "Steve Smith" <[email protected]>
To: <[email protected]>
Sent: Sunday, August 09, 2020 10:57 AM
Subject: Re: Case Study: IBM SYSTEM/360-370 ARCHITECTURE (1987)
The ASCII feature of S/360 probably wasn't used because it's nearly
useless.
What? See my earlier report that no IBM operating system could
turn on the ASCII bit.
The ASCII feature would have been useful in talking to ASCII teletypes.
Turning on ASCII mode caused PACK & CVD to generate ASCII sign
codes and UNPK to generate ASCII zone codes. As far as I can tell,
that's
it. I'd say that the much later PKA & UNPKA instructions make a lot
more
sense than a system option, so I suppose somebody thinks the function
is
useful. But you could always convert zoned decimal with NC/OC or, of
course TR.
ED isn't in my very old S/360 PoOp (A22-6821-0),
no? Look at page 57.
ED, EDMK, TR, TRT, etc etc are all in this manual. See Bitsavers.
but ED certainly came out
soon, long before the ASCII bit was officially dropped. Anyway, I
don't
know whether it supported ASCII mode or not.
It did. Both EBCDIC and ASCII.
But, as I reported earlier, no IBM operating system permitted the
ASCII bit to be set.
