From mboxrd@z Thu Jan 1 00:00:00 1970 From: sms@2BSD.COM (Steven M. Schultz) Date: Wed, 19 Mar 2003 09:46:51 -0800 (PST) Subject: [pups] 2.11BSD "make unix" aborts Error 141 Message-ID: <200303191746.h2JHkpQ02570@moe.2bsd.com> Hi - > From: David Evans > Ugh. > > Am I naive to suggest a rewrite of as? :) Just a little bit It's a thought that used to occur to me fairly often a long time ago. I cured myself of it though after I did the rewrite into its current form (if you think it's bad now you should have seen it before ;)). The biggest problem are the SDI (Span Dependent Instructions). The PDP-11 has 'jmp' (non conditional but no range limit) and 'br' (many flavors of conditional branches but with a +/- 128 byte range). The compiler generates pseudo instructions like 'jeq' and leaves it up to the assembler to figure out if a branch will reach or if a branch around a jump is needed. That's a PITA to handle and is I believe the cause of much ugliness in the assembler. So I'm fought the urge to rewrite the assembler and 'won' - I no longer feel the rewrite urges ;) Cheers, Steven Schultz