The Micropolis DEBUG program is supplied in a non-configured form embedded within the DEBUG-GEN utility program. Before DEBUG can be used an executable version must be obtained by running the DEBUG-GEN utility.
DEBUG requires 4K of contiguous memory address space which may start on any 1 K boundary above the beginninq of the '~DOS a!"ol ications area. DEBUG-GEN accepts a memory space specification and creates a version of DEBUG that uses the specified memory space.
From the MOOS executive, DEBUG-GEN is invoked by entering the filename DEBUG-GEM like an executive statement (see Section 4.1.2) or by entering the command LOAD "DEBUG-GENu follo\'Jed by the command APP.
The program signs on with the message DEBUG GENERATION PROGRAM V5. X.X.
and prompts for the memory address at which the DEBUG will run with the message
ENTER PAGE ADDRESS (2C-F0) ?
Type a two di~it hexadecimal number that corresponds to the high-order byte of the start address where the DEBUG will run. This address may only be on a lK boundary. The program will ignore the lowest 2 bits of the response.
DEBUG-GEN creates a type 14 file on disk unit 0 and fills it with the relocated DEBUG system. The file name is 1I0EBUG-XX" where XX (hex) is the page address entered by the user.
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Example:
MICROPOLIS MOOS V.S. 4.~ - COPYRIGHT 1978
>OEBUG-GEN
DEBUG GENERATION PROGRAM V. S. X. X
ENTER PAGE ADDRESS (ZC-F0)? 70
RUN FILE' NAMED DEBUG- 70
>
In ttlis example a program fi1e named "OEBUG-72r" is created on disk unit 0.
This file is a running DEBUG package which will use the memory space from
79100H to 7FFFH.
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V MICROPOLIS DISK EXTENDED BASIC 5.0 INTRODUCTION
Micropolis Program Development Software consists of two systems, the Micropolis Diskette Operating System (MOOS) and Micropolis Disk Extended Basic. Both systems are supplied on a MASTER diskette included with each Micropolis disk subsystem. The auto-load bootstrap brings MDOS, which is the first system on the diskette, into memory. Control is transferred from MOOS to BASIC by
typing the filename BASIC to the MOOS executive. It is also possib1e to create a BASIC only diskette so that BASIC may be directly loaded by the bootstrap
system~ See Chapter II, Section 2. This chapter describes the Micropolis BASIC interpreter and its associated BASIC programming language.
The Micropolis BASIC Interpreter is a special 8080 machine language program supplied on a master diskette included with the disk subsystem. It provides a simple and powerful means for developing, maintaining and executing BASIC programs on 8080 type microcomputer systems. The user interacts with the Interpreter through a terminal which consists of an input keyboard and an output display that may be video or printed hardcopy. Lines entered at the keyboard may be program lines which are stored in the program buffer or commands for immediate execution. A program in the program buffer may be modified in place, stored as a disk file, retrieved from disk and executed under control of the Interpreter. These functions and others are invoked by entering the apptopriate immediate commands. Elements of the BASIC
Interpreter and its use are described in Sections 5.1 and following.
The original 8ASIC programming language was developed by John Kemeny and Thomas Kurtz at Dartmouth College, Hanover, New Hampshire; "Micropolis Extended Disk BASIC is an elaborated version of that language. BASIC consists of data types, operators, function references and key words which combine to form statements that can be grouped into executable BASIC
programs. The details of these language elements and the rules for com-bining them are described in sections following.
5. 1 ENTERING LINES TO THE BASIC INTERPRETER
The BAS I C Interpreter ; s loaded into the rna in computer memory from ~100S
or booted from a BASIC only diskette. At the end of this procedure the message READY is displayed at the terminal. This means that the Interpreter
is in control and is waiting for a line to be input.
A line consists of not more than 250 characters typed in sequence. The entry of aline is terminated by depressing the RETURN key. If more than
250 characters are typed prior to the RETURN the Interpreter will output the message INPUT OVERFLOW and cancel the entire line.
During the entry of a line each character that is typed is echoed by the Interpreter on the terminal display. If the character typed ;s not part of the BASIC character set (see Section 5.15) it will not be echoed and will not be included in the line entered. The Interpreter also keeps track of the character count as a line is typed and automatically outputs a carriage return / line feed combination to the terminal display when
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the count exceeds the width of the display device. This combination ;s not included in the line count.
Two control features may be used when entering a line.
1) when DEL or RUBOUT key is depressed the next previously typed character will be deleted from the line. A back arrow is echoed to the terminal display for each character deleted.
Neither the deleted characters nor the back arrows are included in the line count.
2) Holding down the control key and typing X (CNTL/X) will cause all of the current line to be cancelled. A carriage return line feed combination is echoed to the terminal display; the Interpreter is positioned to accept entry of a new line.