Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site desint.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcrdcf!trwrb!desint!geoff From: geoff@desint.UUCP (Geoff Kuenning) Newsgroups: net.micro.68k Subject: Re: detecting processor type (68000/68010/etc) in software? Message-ID: <174@desint.UUCP> Date: Sun, 28-Oct-84 16:14:12 EST Article-I.D.: desint.174 Posted: Sun Oct 28 16:14:12 1984 Date-Received: Tue, 30-Oct-84 00:46:42 EST References: <368@foros1.UUCP> <1753@sun.uucp> <217@rlgvax.UUCP> Organization: his home computer, Thousand Oaks, CA Lines: 19 In article <217@rlgvax.UUCP> guy@rlgvax.UUCP (Guy Harris) writes: >I seem to remember some discussion a while ago on the fastest way to do >a block move, which implied that the MOVE.L/DBcc pair was faster on the >68010, but not on the 68000. (Not that the library routine should burn >up a goodly number of the cycles saved by trying to do an RTD and catching >the illegal instruction trap...) Actually, on both the 68000 and the 68010 a series of MOVEM instructions beats a DBRA loop all hollow. This is because the MOVEM instruction makes use of the processor's instruction prefetch buffer to speed up the operation. (This is the reason the 68K makes one extra fetch at the end of a MOVEM into the registers, a source of chagrin to anyone who MOVEM's too close to the end of accessible memory!). -- Geoff Kuenning First Systems Corporation ...!ihnp4!trwrb!desint!geoff