You wrote " the right nibble is not checked", which is incorrect; it is check to to whether to copy it or to ignore it. There is an ambiguity as to how alternate signs are handled.
-- 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 Martin Trübner <[email protected]> Sent: Wednesday, February 25, 2026 4:17 AM To: [email protected] <[email protected]> Subject: Re: ED fail to generate 0C7 External Message: Use Caution Seymour, this citation is about what ED does with left and right nibbles, but it does not contradict what I cited (or said) I say it again in my words: left nibbles must be numeric- right can be anything. This is true for all bytes subject to EDiting Martin Am 24.02.26 um 22:07 schrieb Seymour J Metz: > "At the time the left digit of a source byte is examined, > the rightmost four bits are checked for the existence > of a sign code. When a sign code is encountered in > the rightmost four bit positions, these bits are not > treated as a decimal-digit code, and a new source > byte is fetched from storage when the next pattern > byte calls for a source-digit examination." > > > -- > 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 > Martin Trübner<[email protected]> > Sent: Tuesday, February 24, 2026 12:25 PM > To:[email protected] <[email protected]> > Subject: Re: ED fail to generate 0C7 > > > External Message: Use Caution > > > Seymour, > > > this is what it says: > > The leftmost four bits of each source byte must specify a decimal-digit > code (0000-1001); a sign code (1010-1111) is recog- > nized as a general-operand data exception. The > rightmost four bits may specify either a sign code or a > decimal-digit code. > > Martin > > Am 24.02.26 um 16:38 schrieb Seymour J Metz: >> No, that's not what Pops says. The left nybble must be a valid digit and the >> second nybble gives different results depending on whether it is a digit or >> a sign. >> >> -- >> 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 >> Martin Trübner<[email protected]> >> Sent: Tuesday, February 24, 2026 4:17 AM >> To:[email protected] <[email protected]> >> Subject: Re: ED fail to generate 0C7 >> >> >> External Message: Use Caution >> >> >> Second attempt- maybe this time readable >> >> ED checks all left nibbles for num, the right nibble is not checked, but >> interpreted (digit select, field separator , etc).... see POP. >> >> so 12 3A 56 7B as 4 char packed field is valid (ED does not care for single >> field or multiple fields). >> >> 12 A3 45 67 is not valid because the second left nibble is not numeric >> >> Martin >> >> Am 23.02.26 um 20:48 schrieb martin: >>> ED checks all left nibbles for num, the right nibble is not checked, but >>> interpreted (digit select, field separator , etc).... see POP.MartinFrom a >>> mobile, you can keep tpyos >>> -------- Ursprüngliche Nachricht >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send [email protected] with the message: INFO IBM-MAIN >> >> >> >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email [email protected] with the message: INFO IBM-MAIN > > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email [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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
