80-Bus News

There are two reasons. First of all, it comes free with CP/M, and as yet DRI have not seen fit to supply a free WordStar or GEMPEN. Secondly, it is not slow, and (rareity of rareities) can be driven from a SUBMIT file for most of its functions. I know no other editor which will allow that. Unimpressed cries of “So?”. Let me tell you a story.

It was a dark and stormy night – sorry, I forgot I wasn’t Snoopy. Some time ago, I needed to transfer a suite of programs and data from an Osborne. This was due to the ridiculous disc capacity of that machine, making it unable to cope with the amount of information without major revision of the program. So, as a simple expedient, we thought, “Send it all down to Rory’s GM813, which has 800k drives attached, and let it get on with it”. We (naturally) did not have a modem transfer program, and even if we had, we could not at that time access the status port on the Osborne RS232 line, which modem programs always require. So we broke the programs and data up into 4k blocks, converted to Intel Hex format, and pipped them out through the PIP:. The GM813 received them through the RDR:. 25 files! We did the entire transmission under a SUBMIT file. Similarly at the receiving end, we used another SUBMIT file. We discovered that PIP and the PTP: add 40 nulls to the start of each transmission, and we had to get these off before LOADing the files back to using the [H] option will clear the nulls), we added a few lines to the SUBMIT file to call up ED, strip off 40 nulls from the file in question, exit ED and LOAD the file. Including transmission, the whole job took about one hour, which we spent watching ‘Yes Minister’ on TV, keeping an eye on the computers every ten minutes or so.

Anyway, enough of a digression. Back to our muttons. This book also deals with assembly language and CP/M. I should stress that it doesn’t do this as fully as Miller (reviewed 80-BUS News, Vol 2, No. 4), nor for that matter does the last book, but well enough (apart from 8080 mnemonics) to get you started in the right direction. It has an interesting final chapter giving patches to cure some of the bugs in the standard CP/M transients (the patch for PIP is already available in the HR Utilities disc). If you know a bit about CP/M, and are a computer enthusiast, then this is probably the book for you.

Z80 Assembly Language Subroutines by Leventhal and Saville, published Osborne/​McGraw-Hill is of the usual high standard of Leventhal’s works. It treats Assembly language programming on the assumption that the reader will have had experience in some form of assembly language – it is by way of a conversion manual to the Z80 from other machines. The authors deal with methods of getting the addressing modes not supported in the Z80, which makes for very interesting reading. They include a discussion of common programming errors, and 58 fully commented listings of useful subroutines such as HEX/​ASCII conversion, array addressing etc. These are fully commented, with details of the calling conventions, registers used, and times taken. If only we had had this book four years ago! As an added bonus, it uses Z80 mnemonics!

SuperCalc! The Book by D.H. Beil, published Reston (distr. Prentice-Hall) is concerned with taking the reader through the facilities of SuperCalc. It is very clear and easy to follow, although you have to follow the route the author maps out, for easiest reading. It contains a full description of the SuperCale commands, with detailed examples. I’m using it in conjunction with SC – SC has a good help level, but often one needs the explanation expanded somewhat. For this I refer to Beil. It also contains a full bibliography of articles and books on SuperCalc and other spreadsheets.