Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!metro!ipso!dave
From: dave@ips.oz.au (Dave Horsfall)
Newsgroups: comp.os.cpm
Subject: Help on overlays etc
Message-ID: <1991Apr18.135845.4914@ips.oz.au>
Date: 18 Apr 91 13:58:45 GMT
Sender: dave@ips.oz.au (Dave Horsfall)
Organization: IPS Radio and Space Services.  Sydney, Australia.
Lines: 19

Hello all.  Can someone give me a brief guide to writing overlays and
TSR-like programs for CP/M?  None of the books I have mention the topic,
and user groups died out long ago...  The system is a reasonably standard
CP/M 2.2 system (ZCPR-2 I think), running on a Z80 platform - the Australian
"Microbee", if you've ever heard of it.  Nice little box...

I gather one has to fiddle the top-of-memory pointer after relocating oneself
for the former, and trapping the keyboard-request jump for the latter, but
there my knowledge runs out.  What other things should I have to do?

Since I'm stuck with twin floppies (no provision for a disk without EXTENSIVE
modification), I'd like to use the 64Kb RAM disk that comes with the BIOS as
a small (but fast) paging area of sorts.

Thanks.

-- 
Dave Horsfall (VK2KFU)         VK2KFU @ VK2RWI.NSW.AUS.OC
dave@ips.OZ.AU                  ...munnari!ips.OZ.AU!dave