TOPS-20 Monitor Calls User's Guide


The TOPS-20 Monitor Calls User's Guide is written for the assembly language user who is unfamiliar with the DECSYSTEM-20 monitor calls. The manual introduces the user to the functions that he can request of the monitor from within his assembly language programs. The manual also teaches him how to use the basic monitor calls for performing these functions.

This manual is not a reference document, nor is it complete documentation of the entire set of monitor calls. It is organized according to functions, starting with the simple and proceeding to the more advanced.

Each chapter should be read from beginning to end. A user who skips around in his reading will not gain the full benefit of this manual. Once the user has a working knowledge of the monitor calls in this document, he should then refer to the TOPS-20 Monitor Calls Reference Manual for the complete descriptions of all the calls.

To understand the examples in this manual, the user must be familiar with the MACRO language and the DECSYSTEM-20 machine instructions. The TOPS-20 MACRO Assembler Reference Manual documents the MACRO language. The TOPS-20 LINK Reference Manual describes the linking loader. The DECsystem-10/DECSYSTEM-20 Processor Reference Manual contains the information on the machine instructions. These three manuals should be used together with the Monitor Calls User's Guide, and should be referred to when questions arise on the MACRO language or the instruction set. Another useful reference is Introduction to DECSYSTEM-20 Assembly Language Programming by Ralph E. Gorin, published by the Digital Press. It provides a thorough treatment of assembly language programming for the DECSYSTEM-20, emphasizing the analysis of programs and various methods of program synthesis.

In addition, some of the examples in this manual contain macros and symbols (MOVX, TMSG, JSERR, or JSHLT, for example) from the MACSYM system file. This file is a universal file of definitions available to the user as a means of producing consistent and readable programs.

Finally, the user should be familiar with the TOPS-20 Command Language to enter and run the examples. The TOPS-20 User's Guide describes the TOPS-20 commands and system programs. The TOPS-20 Commands Reference Manual describes all operating system commands available to the nonprivileged user of TOPS-20.