CP/M Plus (CP/M® Version 3) Operating System Programmer's Guide


Brief Contents: Reference guide for experienced 8080/Z80 assembly language programmers who want to create programs for the CP/M-80 platform, using only BDOS (and no BIOS) functions. The guide essentially contains an introduction to CP/M, an introduction to the BDOS system, a descriptive list of all BDOS functions, and some example programs.

Reading suggestions: Please read (study) the first two sections carefully. Only if you fully understand the concepts presented in these two sections, continue reading Section 3, constantly referencing to the previous two sections for better understanding. Only if you know exactly what purpose each BDOS function has, and how some functions relate to each other, continue reading Section 4, which contains program examples. When the reference guide is studied this way, you will benefit the most of its contents.

Printing: Of course, you may want to reference to this guide later on, when you start developing you own CP/M programs. For this purpose, you may want to print the sections on paper for easy reference. Below the sections and their hyperlinks are listed, along with an estimated number of pages per section, based on the A4 paper format (297 x 210 mm), and Microsoft Internet Explorer.


Source Material: This programmer's reference guide is converted from a Portable Document File (pdf) of the OCR'ed version of the Guide. This e-document (and other important documents and programs) can be found at the following web sites:

Remember, the "Unofficial CP/M Web Site" is 'dead', i.e. it is only maintained for archival purposes, but no longer updated.

Conclusion: I hope I have removed most of the OCR errors, and have redrawn the (scanned) figures correctly. If you find any errors, don't hesitate to report those to me via e-mail. Of course, if you simply want to ask me questions concerning CP/M, or want to tell me how great this web site is :-), my e-mailbox is open for those messages too.

René van Belzen
e-mail: hurray@xs4all.nl

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