Newsgroups: comp.sys.apple2.programmer Path: news.weeg.uiowa.edu!news.uiowa.edu!hobbes.physics.uiowa.edu!newsrelay.iastate.edu!vixen.cso.uiuc.edu!sdd.hp.com!decwrl!decwrl!waikato!comp.vuw.ac.nz!actrix.gen.nz!dempson From: dempson@swell.actrix.gen.nz (David Empson) Subject: Re: 16-bit divide in 6502 Organization: Actrix Information Exchange Date: Sun, 30 Jan 1994 11:19:11 GMT Message-ID: References: Sender: dempson@actrix.gen.nz (David Empson) Lines: 23 In article jmk3@crux3.cit.cornell.edu (Jay Krell) writes: > >Think there's one in Eyes' and Lichty's Programming the 65816 I'll give > >it a look - yep pp. 273-4. Should I post it? > > I want a copy of that book. Yes, please post it. Another question, > what zero page locations are usable under P8? If you mean "without BASIC.SYSTEM", then the answer is nearly all of them. The $20-$49 area is used by the monitor, as normal. ProDOS and its drivers use $3A through $4E, but I think it saves anything it uses. SmartPort devices use the $50-$5F area, from what I can remember, but they also save the previous contents. Refer to Appendix A.4 of the ProDOS-8 Technical Reference Manual for a pretty picture of zero page usage. If you're working under BASIC.SYSTEM, there isn't much left which Applesoft doesn't use. -- David Empson dempson@swell.actrix.gen.nz Snail mail: P.O. Box 27-103, Wellington, New Zealand