Path: utzoo!attcan!uunet!husc6!endor!singer From: singer@endor.harvard.edu (Rich Siegel) Newsgroups: comp.sys.mac Subject: Re: What C compiler generates fastest code? Message-ID: <4880@husc6.harvard.edu> Date: 4 Jul 88 15:48:01 GMT References: <14105@shemp.CS.UCLA.EDU> Sender: news@husc6.harvard.edu Reply-To: singer@endor.UUCP (Rich Siegel) Organization: Symantec/THINK Technologies, Bedford, MA Lines: 29 In article <14105@shemp.CS.UCLA.EDU> korfhage@CS.UCLA.EDU (Willard Korfhage) writes: >We just got Lightspeed C (v. 2.15), and someone in the group wrote a >numerical integration program and said it ran on a Mac II at 1/4 the speed >of an unloaded vax 11/750. Quite disappointing, and a bit puzzleing. A Version 2.15 of LightspeedC generates traps to the SANE routines in the Mac II ROM for floating-point calculation. The SANE routines do eventually call the 68881, but they're still very much slower than calling the FPCP directly. The (now available) version 3.0 of LightspeedC has compiler options to generate code for the FPCP and for the 68020. If you use these options, combined with the high-performance math libraries (pats self on back multiple times :-) ) you'll find that the speed of your numerical integrations will be mcommensurate with the Mac II's true speed. -Rich Rich Siegel THINK Technologies Rich Siegel Quality Assurance Technician THINK Technologies Division, Symantec Corp. Internet: singer@endor.harvard.edu UUCP: ..harvard!endor!singer Phone: (617) 275-4800 x305