Path: utzoo!attcan!uunet!samsung!sdd.hp.com!apollo!rehrauer From: rehrauer@apollo.HP.COM (Steve Rehrauer) Newsgroups: comp.sys.atari.st Subject: Re: DHRYSTONE Message-ID: <4b05c8b3.20b6d@apollo.HP.COM> Date: 15 Jun 90 21:35:00 GMT References: <1990Jun15.194338.8548@murdoch.acc.Virginia.EDU> Sender: root@apollo.HP.COM Reply-To: rehrauer@apollo.HP.COM (Steve Rehrauer) Distribution: na Organization: Hewlett-Packard Apollo Division - Chelmsford, MA Lines: 31 In article <1990Jun15.194338.8548@murdoch.acc.Virginia.EDU> gl8f@astsun.astro.Virginia.EDU (Greg Lindahl) writes: >In article larserio@IFI.UIO.NO (LarsErikOsterud) writes: > >>The version of DHRY.TTP posted on comp.binaries must be insane... >>It give 630 on a standard ST and 1300 on a 16 Mhz ST, but all tests >>made by ST freaks here shows over 1000 on a standard ST ??? > >Different compilers give different Dhrystone ratings depending on how >agressive their optimization is. And what version of Dhrystones you're compiling. "Don't believe Dhrystones. Don't believe Dhrystones. Don't believe..." > Dhrystone does some very strange >things, including copying constant strings into word-aligned buffers. >Compilers can "cheat" on this by turning strcpy() into a simple loop. Pshaw -- true cheaters do it as a mess of longword moves, and forego loop overhead altogether. Veritable cheat-masters take v1.1 of Dhry and do the strcpys on a 680x0 as a pair of MOVEMs that burn all 8 D-regs (taking advantage of the fact that the strings are word-aligned, are 31 bytes long, and that the allocated size of source and destination can be padded to 32 bytes (to keep everything word-aligned)). >As a result, you can get results as high as 1500 on a standard ST. As Greg is suggesting: "Don't believe Dhrystones. Don't believe Dhrystones. Don't believe..." -- >>"Aaiiyeeee! Death from above!"<< | (Steve) rehrauer@apollo.hp.com "Spontaneous human combustion - what luck!"| Apollo Computer (Hewlett-Packard)