A good rule of thumb is to be cautious about things that you don't understand. I wonder how many bugs were caused by removing "unnecessary" code.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU> on behalf of Tony Harminc <t...@harminc.com> Sent: Tuesday, September 2, 2025 12:08 PM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU <ASSEMBLER-LIST@LISTSERV.UGA.EDU> Subject: Re: Using (0) to suppress alignment checks in HLASM External Message: Use Caution On Tue, 2 Sept 2025 at 07:22, Binyamin Dissen < 00001773bcccb823-dmarc-requ...@listserv.uga.edu> wrote: > You can teach an old dog new tricks. > > I never knew about this and used the PUSH approach below. > I probably knew of it from other contexts if I thought about it, but it wouldn't have been top of mind. On that note, I imagine few people looking at that explicit 0 index register would know why it's there (and might be tempted to "fix" it as part of a code review/cleanup), so I'd suggest a concise comment on each usage. Something like "Explicit 0 index to avoid alignment msg". Tony H. On Tue, 2 Sep 2025 20:10:29 +1000 Peter Morrison > <0000160d7dfdc207-dmarc-requ...@listserv.uga.edu> wrote: > > :>Hello, > :> > :> Has anyone else used (0) at the end of an RX (or RXY) > instruction to suppress the assembler's alignment check? > :> > :> For Example: > :> > :> DC X'00' force next field to be > unaligned > :> X_UNAL DC AL4(0) Declare an unaligned fullword > :> > :> L R0,X_UNAL > gets a warning > :> L R0,X_UNAL(0) > same generated code (ix reg is 0) but no warning > :> > :> If so, where is it documented? (this is easier than a > <PUSH ACONTROL/ACONTROL NOALIGN/instr/POP ACONTROL> sequence (and takes no > extra lines)) > :> > :>Peter Morrison > > -- > Binyamin Dissen <bdis...@dissensoftware.com> > http://secure-web.cisco.com/1EhX77BB8YgcXV_ic48AWmmlKKwsLXGegrHT1rGhW5pEOvPjBWHY6JCDZDy318e0FYJL-rle42hDlX2C4dXVpZJD2K1rlf8WHX2DH9I43AYSPnBUuo-kHckF5lpupacml1FF-uWCGbU51ubUhyBkZ6Wn8x8j5Tv-aRyL6X0WUb5chI5Baqh_oJ8UIfiy6oAxp-lUr2-eJm7dOuF6EeIiPTH5v5vW5jBy2yIEuBlosFw2f1hlwXlRn-7-seiHi-hslRxYyQuTtqllj6jJTJpdtdaCvR1HzD60d1rul1T3M2qMpQgAYModhrhbL66qNXWKma2rcHZDvfydDqjJJ2YrvI6CS1bPvyiOuTzpmU__AAfexpYyl0TwLol0qL9kCP1EIQ3ntja8e8P92ZN_JRPkcQ1IssbiXbmnzHQW8gkM63IH9uLdOlllmLZTT5PeRDCKA/http%3A%2F%2Fwww.dissensoftware.com > > Director, Dissen Software, Bar & Grill - Israel >
