HC Cassette BASIC

HC Cassette BASIC

HC Cassette BASIC is HomeComp’s first BASIC language for the expanded HC-77B.

It is a compact cassette-loaded integer BASIC designed for the machine’s 4 KB working configuration. It is supplied in TTY and Keyboard/CRT variants, using the same stored-program cassette format.

Requirements

Variant	Required Hardware
TTY build	HC-77B, 3K RAM Expansion, TTY Interface
Keyboard/CRT build	HC-77B, 3K RAM Expansion, Keyboard and Video Display Controller

Loading and Starting

Load HC Cassette BASIC through the HC-77B ROM monitor at $0200, then use:

GO $0200

A cold start displays:

HC-CASSETTE BASIC
]

During execution, front-panel RST returns to the ROM monitor. Use GO $0200 for a warm return to BASIC; the stored program and variables are retained.

BASIC Shell Commands

Command	Meaning
10 PRINT "HELLO"	Add or replace a numbered line
10	Delete a line
G	Run program
N	Clear program
D	List program
S	Save program to cassette
L	Load program from cassette

Listing pauses after fifteen lines with ?CONT. Press Y to continue.

Supported BASIC

STOP
GOTO line
LET A=expression
IF value relation value THEN line
INPUT A
PRINT
PRINT "TEXT"
PRINT expression

Variables are A to M. Values are signed 16-bit integers.

Arithmetic supports one operation per expression:

+
-
*
/

Relations are:

=
#
<
>

# means “not equal”.

Limits

• 31 characters per entered source line
• 384 bytes of tokenised program storage
• integer arithmetic only
• overflow wraps
• PRINT always ends with a new line
• IF compares simple values only

There are no arrays, string variables, DIM, FOR/NEXT, GOSUB/RETURN, REM, END, brackets, operator precedence, chained arithmetic, or multi-item PRINT and INPUT.

Related Pages

• Easter 1978 — Advanced Monitor Tools and HC Cassette BASIC
• Advanced Monitor Tools Cassette
• HC-77B Technical Overview