Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!killer!ames!pasteur!ucbvax!decwrl!labrea!sri-unix!garth!smryan From: smryan@garth.UUCP (Steven Ryan) Newsgroups: comp.arch Subject: Re: The VAX Always Uses Fewer Instructions Message-ID: <810@garth.UUCP> Date: 25 Jun 88 21:28:11 GMT References: <6921@cit-vax.Caltech.Edu> <28200161@urbsdc> <10595@sol.ARPA> <270@laic.UUCP> <20424@beta.lanl.gov> Reply-To: smryan@garth.UUCP (Steven Ryan) Organization: INTERGRAPH (APD) -- Palo Alto, CA Lines: 15 >As you pointed out, there is a need for optimizing assemblers. Strong disagreement--an assembler should be safe, simple, and dumb. If you want an optimiser, use a compiler. What is preferable is separate layer to do the optimisation. The problem with an assembler is that it knows very little. Consider an assembler which replaces a long branch with a different short branch. What if it occurs in a switch? goto next + index goto a ... goto z Also, to properly schedule requires moving code past loads and stores. How can an assembler safely and generally determine what the target of memory reference is?