Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!husc6!rutgers!ames!ptsfa!ihnp4!alberta!ubc-vision!fornax!bby-bc!john From: john@bby-bc.UUCP (john) Newsgroups: comp.sys.intel,comp.sys.ibm.pc Subject: Re: 80827 affects speed of 80286? (July Byte) Message-ID: <135@bby-bc.UUCP> Date: Sat, 4-Jul-87 20:45:50 EDT Article-I.D.: bby-bc.135 Posted: Sat Jul 4 20:45:50 1987 Date-Received: Sun, 5-Jul-87 05:37:03 EDT References: <131@bby-bc.UUCP> <2362@hoptoad.uucp> Organization: Burnaby, British Columbia, Canada Lines: 19 Xref: mnetor comp.sys.intel:292 comp.sys.ibm.pc:5322 > > 2. MSC (4.0, at least) is not capable of taking advantage of '386 advanced > characteristics, and, when compiling large model code, is know to produce > very slow code. Not, perhaps, any slower than anyone else's large model > 8086 and/or 80286 code, but certainly slower than small model. You don't > indicate (or they don't) what compiler flags were used, either. Was it > compiling 80286 code? 8086 code? Stack checks enabled? etc., etc. Sorry, they didn't give that information. I might rephrase my question to be: does the 386 slow down when it is emulating the 286? You would think that with 32 bit memory the 286 mode would get some benefit, e.g. faster instruction access (1 read to get 4 bytes of instruction compared to 2 on a real 286). Or in other words does SHL ax,1 take longer in 16 bit mode than 32 bit mode? john