The rules for assemblers are the same as the rules for any language processor:
1. Correctness trumps speed 2. Make it easier for somebody to figure out how it works and how to change it. Clever code is fine, but document it adequately. 3. When you change platforms or change translators, that which was slow may be fast and that which was fast may be slow. Beware of optimizations that disappear when you upgrade or that impede maintenance. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of Brian Chapman <bchapma...@gmail.com> Sent: Tuesday, August 13, 2019 12:09 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Instruction speeds Thanks Charles and Steve. Now that I am becoming a more experience assembler programmer, I have wondered if I should be greatly concerned about instruction timings or pipeline order, or just simply focus on readability and maintenance. Especially since assembler programming is becoming a dying art. I think I am only 1 of a handful of assembler programmers at my shop with hundreds of mainframe programmers! I think you both answered my question. Thanks! Thank you, Brian Chapman On Tue, Aug 13, 2019 at 11:39 AM Steve Smith <sasd...@gmail.com> wrote: > Write good code and forget about instruction timings. With any luck your > code will have to perform on several generations of architecture and > machines. > > There's a big difference between B- (base-index-displacement) branches and > J- (or BR-) (relative address) instructions. Surely by now, this should go > without saying. Regardless of whether they're "faster" or not, they are > much better, and as that is well-documented, I won't belabor it. > > sas > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN