Yes, you still had to adjust the sign zone after an UNP of a packed decimal field. The ASCII bit was a solution in search of a problem, but it made ene t the time.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Paul Gilmartin <[email protected]> Sent: Friday, June 19, 2026 1:30 PM To: [email protected] <[email protected]> Subject: ASCII bit (was: terminal I/O from Rexx ) External Message: Use Caution On Fri, 19 Jun 2026 14:05:30 +0000, Seymour J Metz wrote: > ... >The ASCII bit in the PSW is the to modify the behavior of decimal >instructions; it has no relevance to telecommunications access methods, which >support a variety of character sets. > Did that affect anything other than the representation of the sign nybble? After UNPK wasn't OC x'F0' or OC x'30' still necessary? Did any software inspect that PSW bit to choose which? Why was that ASCII mode valuable? was there a library of signed decimal (tape?) data needing compatibility support? TCU hardware? -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
