Intel 9800758-02 User Manual

BASIC-SO

REFERENCE MANUAL

Manual

Order

No.

9800758-02

I

Intel Corporation,

Copyright © 1978,

3065

Bowers

1979

Intel Corporation

Avenue, Santa Clara, California

95051

r

Additional copies of this manual

Literature Department
Intel Corporation
3065

Bowers Avenue

Santa Clara, CA

95051

or

other Intel literature may be obtained from:

The information in this document
Intel Corporation makes no warranty

is

subject to change without notice.

of

any kind with regard to this material, including, but not limited
to, the implied warranties of merchantability and fitness for a particular purpose.. Intel Corporation
assumes no responsibility for any errors that may appear in this document. Intel Corporation makes no
commitment to update nor to keep current the information contained in this document.

Intel Corporation assumes no responsibility for the use
an Intel product.

No

other circuit patent licenses are implied.

Intel software products are copyrighted by and shall remain the property

duplication

or

disclosure

is

subject to restrictions stated in Intel's software license,

of

any circuitry other than circuitry embodied in

of

Intel Corporation. Use,

or

as defined in ASPR

7-104.9(a)(9).

or

No part of this document may be copied
written consent

The following are trademarks

and the combination

of

Intel Corporation.

i

ICE
iCS
Insite
Intel
Intelevision
Intellec

of

Intel Corporation and may be used only to describe Intel products:

of

ICE, iCS, iSBC, MCS,

ii

reproduced in any form or by any means without the prior

iSBC
Library Manager
MCS
Megachassis
Micromap
Multibus

or

RMX and a numerical suffix.

Multirnodule
PROMPT
Prornware
RMX
UPI

~Scope

A108/0979/7500

FL

PREFACE

This manual describes and explains the features and conventions
tended
systems using the Intel
Single Board Computer Systems using the Intel Real-Time Multitasking Executive
(RMX-80).

This manual

Intel

and five appendices;

"Introduction" describes the general capabilities of BASIC-80, and its operating en-

vironment.

"Language Elements" describes the ways BASIC-80 represents its instructions, con-

stants, variables, arrays,

"Entering and Editing Programs" shows how you enter text and edit it, at time

entry or after storage.

"Error

error-resolving routines.

"Disk File
files

"Commands and Statements" describes each command and
order.

BASIC-80, as implemented on Intel Intellec

Systems Implementation Supervisor (ISIS-II), and on Intel

is

written for users who require concise, complete information about

BASIC-80 characteristics, and organizes this information into seven chapters

operators, and expressions.

Handling" shows how errors are identified, trapped, and used to initiate

Input/Output"

are created and used.

describes and sh0ws how random and sequential data

microcomp~ter

of

Intel Disk Ex-

development

statem~nt

in alphabetic

of

"Functions" describes each function in alphabetic order.
"Appendix

tions, and codes in tabular format.
"Appendix

variable names.
"Appendix C: BASIC-80 Command Characters" lists BASIC-80 one-character

editing and control characters and their meanings.
"Appendix D:

"Appendix E: Calling Non-BASIC-80 Subroutines" shows how to prepare and call

PL/M-80, FORTRAN-80, and 8080/S085 assembly language subroutines.

"Appendix F: Configuring RMX-80 BASIC-80" shows how to configure BASIC-80

with various hardware systems using

Other Relevant Intel Publications:
The following manuals are required to use

• ISIS-II User's Guide, 9800306, which describes how to operate

Systems Implementation Supervisor" operating system (ISIS-II).

A:

BASIC-80 Error Codes" lists all BASIC-80 error messages, descrip-

B:

BASIC-80 Reserved Words" lists words that cannot be used in

ASCII Codes" lists ASCII codes and their meanings.

RMX-SO.

BASIC-80 with ISIS-Il

or

RMX-80:

the

Intel

iii

•

RMX-80

Real-Time Mulitasking Executive

•

RMX-80

operation

The following manuals may be required if you intend to call subroutines written in
other Intel-supported languages:

• 8080/8085

describes the instructions and directives

User's Guide, 9S00522, which describes how to operate the Intel

(RMX-SO).

Installation Guide, 9803087-01, which describes installation and

of

the Intel Real-Time Multitasking Executive.

Assembly

Language Programming Manual, 9800301, which

of

the 8080/8085 assembler.

• 8080/8085 Macro Assembler Operator's Manual, 9800292, which describes how

to assemble (using

•

PL/M-80

conventions,

• ISIS-II

to use the

•

FORTRAN-80

instructions, conventions, and usage
FORTRAN-SO programs.

Programming Manual, 9S00268, which describes the instructions,

PL/M-80

ISIS-II based

• ISIS-II FOR

how to use the
machine code.

The following manuals are required
of

BASIC-80 described in Appendix F:

•

iSBC

80/30 Single Board Computer Hardware Reference Manual, 9S00611,

which describes how

•

iSBC
Manual,

RMX-80 configuration.

•

iSBC

which describes how
configuration.

•

iSBC

016

9800279, which describes how to map memory to fit the sample

204 Flexible Diskette Controller Hardware Reference Manual, 9S00568,

80/10 Hardware Reference Manual, 9S00230.

ISIS-II) a program written in S080/S085 assembly language.

and

usage

of

PL/M-SO,

and

how

to

create

PL/M-80

programs.

Compiler Operator's Manual, 9800300, which describes how

PL/M

compiler to generate executable machine code.

Programming Manual, 9800481, which describes the

of

FORTRAN-80, and how

TRAN-80

Random

Compiler Operator's Manual, 9800480, which describes

ISIS-II based FORTRAN-SO compiler to generate executable

to

implement the RMX-80 sample configuration

to

configure the iSBC 80/30 under RMX-80.

Access

to

configure the iSBC 204 for the sample RMX-80

Memory

Board Hardware Reference

to

create

• iSBCBO/10A Hardware Reference Manual, 9S00230.

•

iSBC

80/20 Hardware Reference Manual, 9S00317.

•

iSBC

80/20-4 Hardware Reference Manual, 9S00317.

iv

CONTENTS

CHAPTER!
INTRODUCTION

Operating System Interface . . . . . . . . . . . . . . . . . . . . .

Invoking BASIC-80
Manipulating Files from BASIC-80

Listing the Directory

Renaming a File. . . . . . . . . . . . . . . . . . . . . . . . . . .

Changing File Attributes

Deleting a File . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Loading a

Saving a Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER

Program.

2

TO

BASIC-SO

...........................

of

a Disk. . . . . . . . . . . . . . .

..

. . . . . . . . . . . . . . . . . . . . . . . . . . .

..

. . . . . . . . . .

. . . . . . . . . . . . . . . . .

LANGUAGE ELEMENTS

Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Statements.

Functions
Representing
Syntax

.........................................

Numeric

Constants.

Integer Constants

Decimal Integer Constants. . . . . . . . . . . . . . . . . .

Hexadecimal Integer Constants. . . . . . . . . . . . . .

Octal Integer Constants . . . . . . . . . . . . . . . . . . . .

Single-Precision Floating-Point Constants

Double-Precision Floating-Point Constants
Variables
String

String Constants . . . . . . . . . . . . . . . . . . . . . . . . . .

String Variables
Converting
Array Variables

String Arrays
Operators and Precedence

Arithmetic Operators . . . . . . . . . . . . . . . . . . . . .

Relational Operators. . . . . . . . . . . . . . . . . . . . . .

Logical Operators . . . . . . . . . . . . . . . . . . . . . . . .

String
Expressions

Numeric Expressions

String Expressions. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

....................................

Data

...............................

Data

................

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

....................................

Data

...................................

Data

Operator

....

.....

.............................

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

...............................

..............................

............................

. . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . .

of

Evaluation.

.......................

......

.....

. . . . . .

PAGE

..

1-1
1-1

..

1-2

..

1-3

..

1-3

..

1-3

..

1-3

..

1-4

..

1-4

..

2-1

..

2-1

..

2-1
2-5
2-5
2-5

..

2-5

..

2-6

..

2-6

..

2-6

..

2-6

..

2-7
2-7
2-7
2-7
2-8

..

2-8
2-8

..

2-9
2-9

2-10

..

2-11

..

2-11

..

2-11

..

2-12
2-12

..

2-12
2-12

..

2-12

A Subcommand. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E

Subcommand.

Carriage Return. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHAPTER

ERROR

BASIC-80

Syntax Error Messages. . . . . . . . . . . . . . . . . . . . . . .

Overflow, Underflow, and Divide-by-Zero

Integer

Error

Trace Facility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Error
Restarting

HANDLING

Error

Overflow
Underflow

Divide-by-Zero . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operations

Trapping

Simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Program

CHAPTER

DISK FILE

Sequential File

Opening a Sequential File. . . . . . . . . . . . . . . . . . . . .

Writing to a Sequential

Reading from a Sequential

Closing a Sequential File
Random File

I/O

Buffers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Defining a Random
Opening and Closing a Random Disk
Reading from a Random
Writing to a Random

CHAPTER

COMMANDS

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

Messages. . . . . . . . . . . . . . . . . . . . . .

..................................

.................................

............................

..

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Execution

....................

5

INPUT

I/O

I/O

................................

IOUTPUT

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

File.

. . . . . . . . . . . . . . . . . .

File.

. . . . . . . . . . . . . . .

...

. . . . . . . . . . . . . . . . . .

I/O

Field-FIELD

I/O

I/O

File

File

...................

...........

File.

................

6

AND

STATEMENTS

........

. . . . . .

CHAPTER 7

FUNCTIONS

APPENDIX

A

BASIC-SO ERROR CODES

PAGE

..

3-6

..

3-6

..

3-6

..

4-1

..

4-1
4-1
4-1
4-2

..

4-2
4-2

..

4-2

..

4-3

..

4-4
4-4

..

5-1

..

5-1

..

5-2

..

5-2

..

5-3
5-4

..

5-4
5-4

..

5-6
5-6
5-7

CHAPTER

ENTERING

Entering Instruction
Correcting Entry
Editing

Program
D Subcommand
L Subcommand
I Subcommand

H Subcommand. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

X Subcommand. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S Subcommand

K Subcommand. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C Subcommand. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Q Subcommand

3

AND

EDITING PROGRAMS

Lines.

Errors.

Text.

...............................

...............................

...............................

...............................

...............................

. . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . .

..
..
..

..
..

..
..

3-1
3-1
3-2
3-3
3-4
3-4
3-4
3-4
3-5
3-5
3-6
3-6

APPENDIXB
BASIC-SO RESERVED WORDS

APPENDIXC
BASIC-SO COMMAND CHARACTERS

APPENDIXD

ASCII CODES

APPENDIXE

CALLING NON-BASIC-SO SUBROUTINES
APPENDIXF

RMX/80

BASIC-80

v

ILLUSTRATIONS

FIGURE

5-1

Random
E-l Intel Numeric Representation
E-2 8080/8085 Assembly Language Program
E-3

PL/M-80

FORT~AN-80

E-4
F-l Sample Configuration
F-2 Sample Configuration
F-3

Sample Configuration GBASIC.CSD Module

1/0

Characteristics

Program.

TITLE

.................

.................

. . . . . . . . . . . . . . . . . . . . . . .

Program

.....................

BQOPS.ASM Module

GBOOT.CSD Module

.......

....

....

PAGE

'

5-5
E-3
E-5

..

E-6

E-6

F-6
F-7

...

F-8

FIGURE

F-4 Sample BQOPS.ASM Module for PROM-Based

BASIC-80

F-5

Sample GBASIC.CSD Module for PROM-Based

RMX/80

F-6 Sample BQOPS.ASM Module for PROM-Based

iSBC

F-7 GBASIC.CSD Module for PROM-Based

iSBC

F-8 Sample User-Written 110 Driver Routine

.................................

BASIC-80

80/10

BASIC-80

80/10

BASIC-80

TITLE

........................

......................

....... ' ...............

......

TABLES

PAGE

F-9

F-IO

F-IO

F-ll
F-15

TABLE

2-1

BASIC-80 Commands

2-2

BASIC-80 Statements. . . . . . . . . . . . . . . . . . . . . .

2-3

BASIC-80 Functions

2-4

BASIC-80 Metalanguage Elements. . . . . . . . . . .

Numeric Data Types

2-5
2-6

BASIC-80 Operators in Order

TITLE

........................

.........................

.........................

of

Precedence

PAGE

..

..

...

2-1
2-2
2-3
2-5
2-6

2-10

TABLE

3-1

BASIC-80 Editing Subcommands
A-I BASIC-80 Error Codes

D-l ASCII Code List. . . . . . . . . . . . . . . . . . . . . . . . . .

D-2 ASCII Code Definition. . . . . . . . . . . . . . . . . . . .

F-l Sample Configuration Jumper Wiring
F-2 Sample Configuration Memory Requirements

TITLE

..............

......................

..........

PAGE

A-I

..

D-l

..

D-2

F-3

..

F-16

3-2

vi

CHAPTER 1

INTRODUCTION

BASIC-SO
Series II Microcomputer Development Systems, which use the Intel Systems Im­plementation Supervisor (ISIS-II), and for Intel Single Board Computers, which use
Intel's Real-Time Multitasking Executive
applying the computational and input! output capabilities
development system to a wide range of business, information handling, numeric
analysis, and data processing applications.

BASIC-SO
quirements for ISIS-II BASIC-80 include an Intellec Microcomputer Development
System with at least
requirements, both hardware and software, are described in Appendix F
manual.

BASIC-SO
capability, and full disk
written functions can be defined, and up to
Intel-supported languages
language) and called from

is

Intel's implementation

can be used with either the ISIS-II or RMX/SO operating systems. Re-

4SK

of memory space, and one disk drive. RMX/SO

includes

21

commands,

I/O

(both sequential and random access). In addition, user-

(FORTRAN-SO, PL/M-SO, and

BASIC-SO.

of

disk extended BASIC for Intellec and Intellec

(RMX/SO).

39

statements,

25

It

offers a quick method

of

4S

functions, a line-editing

subroutines can

TO BASIC-80

of

the microcomputer

BASIC-SO

of

this

be

written in other

SOSO/SOS5

assembly

Intel integer, single-precision floating-point, and double-precision floating-point
arithmetic standards are all supported, offering flexible combinations of processing

16

speed and accuracy (up to
can have virtually as many dimensions as needed; the only limit on the number
dimensions that can be specified

Hexadecimal and octal integer representation, combined with bitwise Boolean
logical operators, make sophisticated mask operations easy. A full range

is

functions

The disk
files, but also the ability to create, rename, change the attributes of, delete, and list
the directory

BASIC-SO
system with at least

available to provide flexibility in manipulating character data.

I/O

features include not only the ability to read from and write to disk

of

disk files without returning to the operating system.

requires

an

4SK

digits in the range ± 2.2 x

is

the 255-character program statement length.

Intellec or Intellec Series II microcomputer development
RAM and ISIS-II operating system (version 3.4 or later).

-308

to ±

1.S x 10

308

).

Arrays

of

of

string

Operating System Interface

You can invoke
for boot loading upon restart. Once BASIC
the disk file-handling functions as well as the ability to load and save programs.

BASIC-SO

from ISIS-II, or configure

is

running, you have access to many

RMX-SO

BASIC-SO

in PROM

of

Invoking BASIC-80

Once you configure RMX/SO BASIC-SO, you
restart.

will

always enter

BASIC-SO

upon

1-1

Introduction to BASIC-80

To

invoke BASIC-80 from ISIS-II, enter the name
BASIC interpreter. Options also allow you to specify the name
a program to be loaded after
BASIC-80's work area. The format

BASIC-80

of

the command is:

of

the file that contains the

of

a file that contains

is

running, and upper memory limit for

BAS

IC-80

-BASIC

is

the ISIS-II command prompt.

enter the command.

BASIC

specifies the name

filename

is

an optional parameter

loaded and run after

MEMTOP(address)

is

an
that
number.
interpreter, and less
system.

Examples

[filename] [MEMTOP(address)]

It

is

displayed automatically before you

of

the file that contains the

that

specifies the name

BASIC-SO

is

running.

BASIC-SO

of

optional parameter that specifies the upper bound

BASIC-80 can use. Address can be either a decimal

It

must be greater

than

than

3800H plus the number

OBEBFH in a

48K

system

or

interpreter.

a file that

of

the memory

or

hexadecimal

of

bytes in the

OF6BFH in a

is

to be

64K

1.

If

the interpreter

-BASIC

2.

If

the situation

a disk in drive

-BASIC

3.

If

the

situation

using memory beyond address

-BASIC

If

a fatal ISIS-II error occurs while BASIC-80

initialized and the contents

is

in a file named BASIC

is

the same as

1,

but

you want to run a file named ANLYZE on

1:

:F1

:ANL YZE

is

the same as 2,

but

you also want to prevent BASIC-80 from

54400:

:F1

:ANLYZE MEMTOP(54400)

of

the BASIC-80 work area

on

a disk in drive 0 enter:

is

running, ISIS-II

is

lost, including any

is

re-

program editing you have done since you last entered a save command.

Manipulating Files from BASIC-SO

BASIC-80 lets you list a disk directory, rename a file, change the attributes of a file,

and delete a file. These functions can also be performed using

of course.

ISIS-II

or

RMX-80,

1-2

BASIC-SO

Introduction

to

BASIC-SO

Listing the Directory

To list the directory
assumes drive 0 if you

DIR
NAME.EXT

ALPHA
ATTRIB
BASIC 178

COpy
DCOPY
DELETE

DIR
DSORT
EDIT

.MAC
INDEX
NED
RENAME

of

a Disk

of

a disk, enter DIR followed by the drive number. BASIC-80

don't

specify:

RECS LENGTH

31
38

64
32
37
46
11

5

.I

46
79
21

3728
4677

22571

7967
3961
4501
5728
1264

469

5669

469

2438

ATTR

Renaming a File

The RENAME command lets you change the name

to a new filename. The directory listing also changes to the new filename. In the ex­ample below, file

:FI:PROG

changes to :FI:MYPROG:

of

any file from an old filename

RENAME

":F1

:PROG"

to

":F1

:MYPROG"

Changing File Attributes

With the BASIC-80 A TTRIB command, you can protect a file from overwriting,

deletion,
invisibility attribute,
set the format attribute,
or FORMAT commands. The system attribute,
to a disk when the disk

or

being renamed by setting the write-protect attribute

"I",

the file will not appear when the directory

"F",

the file will copy to a disk formatted with the IDISK

"S",

makes the specified file copy

is

formatted by the FORMAT command or copied with the

"W"

.

If

you set the

is

listed.

If

you

COPY command.

For each attribute, the format

enabled, where X

ATTRIB

is

either W, I, S,

"filename",

is

"XO"

or

F. The format

"XO"I"X1"

if the attribute

of

A TTRIB

is

disabled,

is:

"Xl"

if it

Deleting a File

If

you want to get rid

it

and remove its listing from the directory. Once a file or program has been killed, it
cannot be recovered. The format
filename in quotation marks. For example, to delete a file named ANL
disk in drive

1,

enter:

of

a file or program, you can use the KILL command to delete

of

the KILL command

is

KILL followed by the

YZ

on

the

is

KILL

":F1

:ANLYZ"

1-3

Introduction

to

BASIC-80

Loading a Program

BASIC-80

The LOAD command loads a
stored in either ASCII
a disk in drive

LOAD ":F1 :ANLYZE"

OK

You can now run, list, or edit the program.

Saving

The SAVE command copies your program from Intellec memory to disk. You must
specify a filename, enclosed in quotation marks:

SAVE ":F1 :ANLYZ"

The SAVE command can also be used to list the contents
printer or other output device. For example, to list the current file on a line printer,
you would enter:

SAVE

1:

a Program

":LP:"

or

,A

BASIC-SO

internal format.

program from disk. The program can be

To

load a program named ANL YZE from

of

the current file on a line

4"4;0"1"

You can only write data to one disk in any disk drive each time you invoke

If

BASIC.

another, and try to write to the new disk, you lose all data on the
The exception to this
ble to change a disk on a drive if that drive has not been written to since

another drive has been written to.

gram writes

another and write on it, the contents
however, your program wrote on a disk in drive 1 between writing on the

different disks in drive

you write to a disk in a given drive, remove that disk and insert

new

disk.

is

on systems with more than one drive.

As

an example, if your

on

a file in drive 0, and you then remove that disk, insert

of

that second disk

0, there would be no problem.

It

is

permissi-

BASIC-SO

will

be lost.

pro-

If,

1-4

There are no restrictions on reading from disks.

CHAPTER 2

LANGUAGE ELEMENTS

A BASIC-80 program consists

of

instructions, which tell BASIC-80 what to do, and
data, which gives BASIC-80 the inform.ation necessary to do it. This chapter
describes the different types

of

instructions and data, and shows how to represent

them.

Instructions

BASIC-80 performs work by interpreting user-provided instructions. These instruc­tions are divided into three categories: commands, statements, and functions. These
instruction types are described in the following topics; the individual instructions are
described in detail in Chapters 6 and 7.

Commands

Commands are executed as soon as you enter them; they alter
grams or files. Most commands can be used in program statements, but many
them halt program execution and force variables to zero or null.

2-1

Table

lists the BASIC-80 commands.

Statements

Statements are executed when they are encountered during program execution. They

of

make up most
commands.

the instructions

of

a program. Most statements can be entered as

or

direct entire pro-

of

Table 2-2 lists the BASIC-80 statements.

Table

2-1. BASIC-SO

Command
ATTRIB

AUTO

CLEAR
CONT
DELETE

DIR

EDIT

EXIT
KILL
LIST

LOAD

Changes the attributes of a file.
Automatically

statements.
Sets aside memory
Continues execution
Deletes a

program.
Displays a

files
Specifies a program statement

be changed.
Retu rns
Deletes a file from disk.
Displays a

program.
Retrieves a file from disk.

Description

numbers program

line

or

list

on

of

a disk.

to

operating system .

line

or

for

strings.

after

BREAK.

lines

from a

all non-invisible

lines

of

a

Commands

ATTRIB
AUTO

CLEAR
CONT
DELETE

DIR1

to

EDIT

EXIT
KILL ":F1 :STAT"
LIST

LOAD ":F1 :DATES"

"~F1

25,500

2000

700~875

170

300-400

Example

:STAT",

"W1"

Language Elements

BASIC-80

Table 2-1. BASIC-80 Commands

Command
MERGE Combines file program with current

NEW

NULL
PRUN

RENAME
RENUM Changes program line numbers. RENUM
RUN
SAVE Stores program
TRON
TROFF
WIDTH

program.
Deletes

variables.
Specifies nulls added to a line. NULL
Executes program in

Changes

Executes program.

Turns on trace facility. TRON
Turns off trace facility. TROFF
Changes width

Description

MERGE

current

program, clears

ROM. PRUN

file

name. RENAME ":F1 :SOUP"

or

file on disk.

of

display line.

NEW

RUN
SAVE ":F1:INVEN"

WIDTH

Table 2-2. BASIC-80 Statements

Statement

CLOSE
DATA

DEF

DEFDBL

DEFINT

DEFSNG

DEFSTR

DEFUSR
DIM
END
ERROR

FIELD
FOR-NEXT-STEP

GET
GOSUB
GOTO

TH

EN-ELSE

IF-

INPUT

LET

Closes
Identifies values that can be assigned

with a READ statement.
Defines a user-written function.

Defines variable names starting with
the given
floating-point.

Defines variable names starting with
the given

Defines variable names starting with
the given
floating point.

Defines variable names starting with
the given
names.

Defines non-BASIC subroutine.
Allocates space for array variables.
Concludes program.
Simulates errors with given

number.
Allocates space in random file buffer.

Creates a loop.

Retrieves data from

Transfers execution to subroutine.
Transfers execution to line number.
When the expression specified is true,

the statement executes;
second statement executes.

1.

Prompts for terminal
program

2.

Reads data from sequential file.

Assigns value to variables.

one

letter

letter

letter

letter

Description

or

more files.

as double-precision

as integer.

as single-precision

as string variable

disk

file.

if

false, a

input

error

in

(Cont'd.)

":F1:TIME"

20

4EOOH

80

CLOSE 3
DATA

DEF

=

DEFDBL

DEFINT

DEFSNG B-H,

DEFSTR

DEFUSR 0 =
DIM
END
ERROR

FIELD #3,20
FOR

NEXTI

GET#2,4
GOSUB
GOT0400
IF

A>B THEN

ELSE PRINT

INPUT
INPUT

LET A=52

Example

TO

":F1

Example

9,0,

"JUNE",

FNRT

(R1,

R-Z

I-N

K-O

12

TO

550

B,

A$,

R2)

R2)

X,

Y

4EOOH

AS

A$

5 STEP.5

2~0

">"

C

B$,

C$

R1

*R2/(R1 +

char (25,10,25)

1=1

A,
#1,

:NUTS"

.33

2-2

BASIC-SO

Language Elements

Statement

LINE INPUT
lSET

ON

ERROR

ON-GOTO

ON-GOSUB

OPEN
OPTION BASE
OUT
POKE
PRINT

PRINT USING

PUT
RANDOMIZE
READ

REM

RESTORE

RESUME
RETURN

RSET
STOP
SWAP

WAIT

Table 2-2. BASIC-80 Statements

Description

Enters entire line from a disk
left

justifies

Traps
error-resolving routines.

Transfers execution
for expression

Transfers execution
for expression

Creates sequential
Starts arrays at 0
Writes values
Writes byte

1.

Displays

2.

Stores data in sequential
disk file.

Displays

Stores data in random disk file.
Initializes random number generator.
Assigns values from DATA statements

to program variables.
Comments in program

Resets pOinter for reading DATA
statements.

Restarts execution after errors.

Transfers control back

following last GOSUB.
Right
Halts program execution.
Exchanges values of two variables of

similar type.
Halts execution until port changes.

errors

to

text

justifies

text

in random file buffer.

by

to

X.

to

X.

or

or

1.

to

I/O

ports.

memory location.

text

on terminal.

according

text

in random file buffer.

file.

branching

Xth line number

Xth subroutine

random

disk

to

given format.

text

to

statement

files.

(Cont'd.)

Example

LINE INPUT
LSET

A$ = B$

to

ON

ERROR

ON

X GOTO

ON

X GOSUB

OPEN

"R",
OPTION BASEO
OUTOOFO,12
POKE

OA077,
PRINT

A,

B,

PRINT

#4,

A$,

PRINT USING "$$##,##;

125.38,21.14.6.10
PUT

#3,

A$,
RANDOMIZE
READ

A,

K1,

10

REM

REM

l$ = MK$

A1#,

THIS
A REMARK

04H,

20
RESTORE

RESUME
RETURN

RSET
STOP
SWAP

WAIT 1,

A$

GOTO

900

460,

480

220, 240,

1,

":F1:TRACE"

72

C

B$,

C$

B$

C$

l%,

Z

IS

B2#

OAH

260

Functions

ABS
ASC

ATN
COSl

CHR$

CINT
COS
CSNG
CVD

CVI
CVS

Table 2-3. BASIC-80 Functions

Returns

Absolute value.
ASCII code

specified string.
Arctangent, in radians.

Double-precision floating-point value.
Character corresponding to the specified

code.
Integer value
Cosine,
Single-precision floating-point value.
Double-precision floating-point value equal to

8-byte string
Integer value equal
Single-precision floating-point value equal to

4-byte string

in

radians

of

the first character of the

A$

to

2-byte string

A$

A$

ASCII

ABS(X)
ASC(A$)

ATN(X)

CDSl

(X)

CHR$

(X)

CINT(X)
COS

(X)

CSNG

(X)

CVD(X#)

CVI

(X%)

CVS(X!)

Example

2-3

Language Elements

BASIC-80

Table 2-3. BASIC-80 Functions (Cont'd.)

Functions

DSKF

EOF
ERL
ERR
EXP
FIX
FRE

HEX$
INP
INPUT$
INSTR$
INT
LEFT$
LEN
LOC

LOF

LOG
MID$
MKD$

MKI$
MKS$

OCT$

PEEK

POS
RIGHT$
RND

SGN
SIN
SPACES
SPC
SQR
STR$
STRING$

TAB
TAN
USR
VAL
VARPTR

Returns

Number
drive

-1 if end-of-file; 0
Line
Error
e
Integer value
Number

bytes in string space

String equal to hex value

Reads a byte from port (X)
Inputs (X) characters from file
Position

Integer value

Leftmost
Character length
Current record

Sectors read
quential file

Number
data sectors in sequential file

Natural log

J characters, starting at

B-byte string equal to double-precision
floating-point variable (X!)

2-byte string equal to integer variable (X%)
4-byte string equal to single-precision

floating-point variable (X!)
Octal equivalent
Single byte from memory location
Position
Rightmost
Single-precision random number between 0

and
Sign
Sine
String
String
Square root
String equal

Character

of
Spaces

Tangent value

References
Numerical value
Memory address

of

128-byte sectors free on disk

(X)

number

to

the (X)th power.

1.
of
of

A$,

of

code

of

last error.

of

of

bytes in memory

of

(X$)

of

(X)

characters

or

X.

of

records in random file

of

(X)

of

cursor after last PRINT.

(1%)

(X)
(X)

of

(1%)

spaces

of

(X%) spaces

of

to

X,

Y% times.

Y%

to

(X)

position on terminal

user

or

if

not

(for file

X).

last error.

(X).

(X)

or

X.

X$

(Y)

to

X.

A$

(X)

first

24

number

Number

character

(X$)

of

(X%)

within

(Y$)

(X)

of

(A$)

of

(X$)

number

written since last OPEN in se-

of

decimal argument

characters

(X)

(X)

times-or

of

(X)

subroutine 0

of

(X$)

of

(X)

in random file

I,

of

string

of

the

DSKF(X)

A

= EOF(X)

ERL
ERR
EXP
FIX

of

FRE

HEX$(X%)
INP(X)
INPUT$ (X,
INSTR$
INT(X)
LEFT$
LEN
LOC

X.

of

LOF (X)

LOG
MID$

MKD$ (A$)

MKI$ (A$)

MKS$(A$)

OCT$(X)
PEEK
POS
RIGHT$
RND

SGN
SIN
SPACE$(I%)
SPC(X%)
SQR
STR$
STRING$ (Y%,

STRING$ (Y%,
TAB
TAN
AX = USR
VAL
VARPTR(X)

Example

(X)

(X)

(X)

Y)

(X$,

Y$)

(A$,

X)

(X$)

(X)

(X)

(A$,

I,

J)

(X)

(dummy argument)

(X$,

1%)

(X)

(X)

(X)

(X)

X)
A$)

(X)

(X)

12

(A1,

A2)

(X$)

2-4

BASIC-SO

Language Elements

Functions

Functions are built-in routines that return a value based on the argument or
arguments supplied. They can be used to form expressions with either commands
statements.

Table

2-3

BASIC-SO

lists the

includes both numeric and string functions.

BASIC-SO

functions. In addition to these, up to

10

user-written

or

functions can be defined with the DEFFN statement.

Representing Data

The instructions described in the previous topics tell BASIC-80 what to do; to carry
out these instructions, you must also provide data in a specific fashion. Intel
BASIC-80 includes constant and variable values, in either numeric or string format;
allows these values to be grouped into arrays; provides for conversion from one data
type to another; and allows these values to be combined into expressions using
arithmetic, relational, and logical operators.

Syntax

BASIC-SO

accepts instructions and data in a specific format. This format, called

syntax, must be followed to obtain useful, predictable results.

of

superset
language elements used to illustrate

ANSI Minimal BASIC syntax. The table below describes the meta-

BASIC-80 syntax.

Table 2-4. BASIC-80 Metalanguage Elements

Condition

An

instruction that requires no argument is

shown by itself in uppercase letters.
If

an

argument must be provided, the descrip-

tion

of

follows the instruction.

If

the argument is enclosed in brackets.

If more than one type of argument can be
specified, the choices are separated by ver-

tical lines.

If
signify repetition.

the argument, in lowercase letters,

an

argument is optional, the description of

an

argument can be repeated, three dots

RESTORE

GOTOline

POKE

address, value

RESUME

SAVE

PRINT

READ

ON

[line number]

"filename"

expressionlvariable

data [,data] ...

variable GOSUB line [,line] ...

Numeric Data

BASIC-SO

categories, there are three types

point, and double-precision floating-point.

accepts numeric values as either constants or variables. Within these two

of

representation: integer, single-precision floating-

BASIC-SO

Example

[,A]

syntax

is

a

Using the DEFINT, DEFSNG, or DEFDBL statements, you can define a range of

letters to signify integer, single-precision floating-point, or double-precision

If

you

don't

floating-point numeric variables.
it with a one-character suffix when you use the variable or constant letter name.
you

don't

specify numeric type, the default

define numeric type, you can specify

is

single-precision floating-point, as if a

If

DEFSNG A-Z instruction had been given.

Table

2-5

summarizes

the

characteristics and methods of specifying numeric data

types.

2-5

Language Elements

Constants

Constants are numeric values that do not change during program execution. A con­stant can be a decimal integer, hexadecimal integer, octal integer, single-precision
floating-point number, or double-precision floating-point number.

Table

2-5.

Numeric

Data

BASIC-80

Types

Numeric

Integer

Integer

Integer

Single-precision

(7

Double-precision floating-point
(16

(decimal)

(hexadecimal)

(octal)

digits

precision)

digits

precision)

Type

floating-point

Range

-32768
+32767

Oto

FFFFH

Oto

1777770
±1.2 x

±

3.4 x 10

±

2.2

x 10-

± 1.8 x

10-

10

to

38

308

38

308

Storage

Required

2 bytes
2 bytes -

2

bytes

to

4

bytes

to

8 bytes DEFDBL

Definition

DEFINT % X%

-

DEFSNG

Integer Constants

Integer constants are whole numbers in the range

constant requires two bytes

for integers and integer arithmetic

of

memory. Because the storage requirements are lowest

is

much faster than floating-point arithmetic, it's

a good idea to use integer representation wherever possible.

-32768

to 32767. Each integer

Decimal Integer Constants

To identify a constant as a decimal integer constant, add the suffix
integer value.

Suffix

070

Examples

9463%

H

OFF4H

7720

0

!

X!

9436.5!

9.4365E03

#

X#

9436.5#

9.4365D03

to the decimal

2-6

Some decimal integer constants are:

Hexadecimal Integer Constants

Hexadecimal integer constants are identified by the suffix H following the numeric
value. The characters

0-9 and A-F (representing the decimal values

hexadecimal digits. Each character represents 4 bits

be a decimal digit, so

it

may be necessary to

add

a leading

teger constants are:

Hexadecimal

1FH
OC76H
7H

Decimal

Equivalent

3190

of

data. The first character must

o.

31

7

10-15)

are used as

Some hexadecimal in-

BASIC-80

Language Elements

Octal Integer Constants

Octal integer constants are identified by the suffix Q following the numeric value.
The numerals
octal iQteger constants are:

0-7

are

used as octal digits. Each digit represents 3 bits

of

data.

Some

Octal

7720
44440

7Q

Decimal

Equivalent

506

2340

7

Single-Precision Floating-Point Constants

Single-precision floating-point constants are identified by the suffix ! following the
numeric value, by
the presence
point numbers

of

digits

accuracy.

Each single-precision floating-point constant requires
Because this is
stants,
arithmetic,

and

it's

point operators.
Some single-precision floating-point constants are:

142!

-1.414

6.259371

the

letter E identifying the exponent in scientific notation,

of

a decimal point in a number having seven

in

the

range ± 1.2 x

half

the storage required

because single-precision arithmetic

a good idea

to

use single-precision wherever possible for floating-

10-

38

to ± 3.4 x

by

double-precision floating-point con-

is

E-09

or

fewer digits. Floating-

38

10

are represented with seven

four

bytes

of

quicker

than

double-precision

or

by

memory.

Double-Precision Floating-Point Constants

Double-precision floating-point constants are identified by the suffix # following the
numeric value, by
having more

± 1.8 x

10

308

Each double-precision floating-point constant requires eight bytes

the

letter D identifying the exponent in scientific notation,

than

seven digits. Floating-point numbers in the range ± 2.2 x

are represented with

16

digits

of

accuracy.

10-

of

memory. Some

or

308

by

to

double-precision floating-point constants are:

-2.001317921012
11235813213455

24.2#

Variables

Numeric variables represent numeric values

tion. These

can

be

of

three types, like numeric constants: integer, single-precision

floating-point, or double-precision floating-point. Numeric variables are repre-

sented by one

or

two characters followed by

first character must be a letter; the second, which

alphanumeric character.

If

the variable name contains more
besides a type identifier suffix, the rest
No words used as

BASIC-80 instruction words may be used within variable names.

that

can

change during program execu-

an

optional type identifier suffix.

is

optional, may be any

than

two characters

of

the variable name characters are ignored.

The

2-7

Language Elements

If

a variable

NEW,

Individual variables can be specified by individual type identifier suffixes, which

override group type identifiers used to specify blocks
these suffixes.

is

referenced before it has been assigned a value, its value

RUN, CLEAR, LOAD, and MERGE instructions set all variables to zero.

of

variables. Table

is

zero. The

2-5

shows

BASIC-80

Blocks
single-precision,
statements. The general form of these statements is: DEFxxx m[-n], where n
letter A through Z,
(Le., the block L-Q
a certain letter or letters may be defined as one type.

The variable default type
at the start
should define them
type identifiers
override any variable block type assignment.

Note that A$,
type for variables beginning with the letter A
the same variable.

To economize on memory space and execution time, you should use integer
representation rather
rather

of

variables beginning with specific characters can be specified as integer,

or

double-precision with the DEFINT, DEFSNG, and DEFDBL

and m is
is

of

a given program.

at

(%

for

AOJo,

A!, and

than

double-precision, when this

any letter A through Z that precedes n in the alphabet,

legal, but Q-L

is

single precision, as if a DEFSNG A-Z had been executed

the start

integer,!

AI

than

single-precision representation,

is

not). In this way, all variables beginning with

If

certain variables should be of another type, you

of

the program to prevent errors. In all cases, the

for single-precision, and I for double-precision)

are four different variables.

is

single precision, then A and

is

possible.

If

the default variable

and

single-precision

is

A!

any

are

String Data

BASIC-80 accepts strings
either constants or variables.

of

characters as data. Like numeric values, strings can be

String Constants

A string constant
marks cannot be used within string constants. String constants can be up to
characters long. Some string constants are:

"This

"48, 23H, 373799"

is

a group

is a string

of

characters, enclosed in quotation marks. Quotation

constant."

255

String Variables

String variables are string values which can change during program execution. A

is

string variable name
followed by
first two are read.

String variables can contain strings
BASIC-80, however, there
command must
some examples of assignments to

A$ = "Enter

B$ = "40

NAMES$ =

$.

If

be

* 1. 7234E +

one or more characters, the first

more

than

two characters are entered as a variable name, onlv the

is

only storage space for 100 characters. The CLEAR

used to increase the amount of available string space. Here are

strip.g variables:

next data

"Warren,

string"

3"

Mark, Evan"

of

from 0-255 characters. When you first invoke

of

which must be a letter,

2-8

BASIC-SO

Language Elements

Converting Data

It

is

sometimes useful to convert one type
these conversions with the HEX$, OCT$, CHR$, STR$, VAL, CVD, CVI, CVS,
CDBL, CSNG, CINT, MKS$, MKD$, and MKI$ functions.

of

data into another.

BASIC-SO

suppo. I...,

The HEX$ and

OCT$ functions return a string

respectively, that represent the numeric argument. The

of

string
function returns the numeric value

CHR$ returns the
The CVI,

sion floating-point,

decimal digits that represent the decimal value of the argument. The VAL

of

the string argument, if the string

ASCII equivalent

of

an integer argument, between 0 and 255.

CVS, and CVD functions convert a given string into integer, single- preci-

or

double-precision floating-point numeric values, respectively.
These functions are used to retrieve numeric values from the
when doing random disk

110.

of

hexadecimal and octal digits,

STR$ function returns a

is

a number.

input/

output buffer

The MKI$, MKS$, and MKD$ functions convert integer, single-precision floating­point, and double-precision floating-point numeric values, respectively, into a
string. These functions are used to store humeric values in the input/output buffer
when doing random disk

You can convert a numeric variable (integer, single-precision floating-point,
double-precision floating-point) to any

110.

of

these types by using the variable in an

or

ex-

pression with the CINT, CDBL, or CSNG functions:

A# =

CDSl

l4!

= CSNG

VAR5 = CINT (VAR5)

(A%)

(l4)

Array Variables

An array

is

a group

of

variables identified by the same name, specified by subscripts
that define their position in the array. An array variable can have as many dimen­sions as will fit on a single line. An array variable

is

specified by following a variable
name with as many subscripts as there are dimensions. A subscript must be an in­teger value, and enclosed within parentheses

square brackets.

If

there

is

more

or
than one subscript, separate them with a comma. Expressions can be used to specify
subscripts; they are rounded to integer form. Here are some array variables:

X

(10)

R1

(5,4)

Y(I,1)

SA(I + 3,X(10))

BASIC-SO
defined as
BASE

normally indexes arrays from zero; that is; the first element in

O.

To start arrays

at

one in BASIC-SO, enter the instruction OPTION

1 in your program before you dimension or reference any arrays.

an

array

is

The DIM statement allocates array space and specifies the maximum allowable

If

subscript for a given dimension.
formally dimensioned,
examples

An attempt

of

the DIM statement:

DIM X(15)
DIM R1(12,8)
DIM K(17,24)

to

specify

BASIC-SO

an

array variable whose subscripts are larger than the dimen­sioned value, or which exceed
OF

RANGE error

message~

an array variable

allocates

10

in the default mode, causes a SUBSCRIPT OUT

an

index

is

referenced before it has been

of

10

for each dimension. Some

2-9

Language Elements

String Arrays

Like numeric arrays, string arrays can be dimensioned with the DIM statement. The
format for dimensioning a string array

If

you

If

this value

DIM A$(5,25,40)

don't

execute a DIM statement, a default

is

then exceeded, an error message will result.

Table

2-6. BASIC-80

is

the same as for numeric arrays:

of

10

for each subscript

Operators

in

Order

of

Precedence

is

assumed.

BASIC-80

Order

1.

2·.

3.

4.

5.

6.

7.

8.

Operator
Expressions in parentheses.
Exponentiation, as shown in the example,

where A is raised to the B power.
Negation, represented by the minus sign.
Multiplication and Division, represented by

an

asterisk

Integer

backslash (

verted to integer
truncated to an integer.

Integer Modulus, represented by MOD.
Both arguments are converted into in­tegers. The
the first is divided by the second.

Addition and Subtraction, represented by

(+) and minus

Relational Operators. These are listed
without precedence. For all relational
operators, the result is -1
false. The arguments A and B must
strings

Equals sign: Used to

(*)

and a slash

division,

).

Both arguments are con-

result is the remainder when

(-)

signs.

or

both numeric variables.

(I)

respectively.

represented

values and the result is

if

true, and 0 if

test

for equality.

be

by

both

Example

(A+B)

AtB

-A

A*B
AlB

a

A\B

AMODB

A+B

A-B

A=B

2-10

Greater Than: Used to test magnitude be­tween two arguments. The
sign faces the posited greater

Less Than: Used to test magnitude between
two arguments. The
sign faces the posited

Not Equal: Used to test for inequality be-

two

tween
Greater Than or

magnitude down to the
argument.

Less Than
magnitude up to the

argument.

In

the Logical Operators below, the arguments are converted to 16-bit, signed
complement integers
converted to the same format. The operations are performed one
paring the nth bit

of

X with the nth bit of

arguments.

Equal To: Used to test

or

Equal To: Used to test

in

the range -32768 to

large end

value.

small end of the

less.er value.

level

of

the second

value

of

the second

+32767.

Y.

The result of the operation is

of

the

bit

at a time, com-

A>B

A<B

A><B
A<>B

A=>B
A>=B

A=<B
A<=B

two's

BASIC-80

Table

2-6.

BASIC-SO

Operators

in

Order

of

Precedence

Language Elements

(Cont'd.)

Order

9.

10.

11.

12.

13.

14.

Operator

Logical NOT, used
argument.

Logical
and the nth bit

Logical
Y equals

Logical exclusive OR, used
the nth bit of X or the nth bit
both.

Logical implication, used to test
of

Logical equivalence, used to
bit

AND,

used

of

OR, used to test

1.

X is on, then the nth bit

of X equals

the

to

Yare

nth

to

invert a given

test

if the nth bit

both on.

if

the nth bit of X or

to

of

of

Y is on.

test

bit

of

Y.

test

if

Y =

1,

if

the nth bit

if the nth

of

X

either

but not

NOT-1

1ANDO=O

150RO=15

15XOR7=

OFOFOH

OFOFH

Example

=0

8

IMP

OOFFH=OFFFOH

EQV.OOFFH=OFOOFH

Operators and Precedence of Evaluation

Complex expressions may be formed by combining constants and variables with
arithmetic, logical, relational, and string operators.
precedence to insure orderly and predictable evaluation when analyzing complex
pressions. This order

of

precedence may be overridden
within the parentheses are evaluated first. The numeric operators (arithmetic,
logical, and relational) are listed in order

of

precedence

BASIC-SO

by
in

follows an order of

parentheses; any elements

Table 2-6.

ex-

Arithmetic Operators

There are seven arithmetic operators in
arithmetic operation on two numeric expressions. They are evaluated before the
relational or logical operators, and if two operators

BASIC-SO, they are evaluated from left to right. Table

by

of

operators in order

precedence. Some examples

A = 8*(C*2.49)
K1=(L+M)
RS

= (83*

Et

S

.S)

BASIC-SO,

of

arithmetic operators are:

each performing a familiar

of

equal precedence are found

2-6

lists the arithmetic

Relational Operators

There are six relational operators in

-1

expressions and return a

if the premise
structions to direct program execution according to either result. The relational
operators are evaluated after the arithmetic operators, and if two operators with the
same order
Table

IF
IF

IF

of

precedence are given in an expression, they are evaluated left to right.

2-6

lists the relational operators, and some examples are given below:

(A*2.2)<>8*81

THEN
INT(A1) = INT(81) THEN
A>

B THEN

IF

8>(C*

BASIC-SO,

220

A=B

VA#)THEN

which test relationships between two

is

true, a 0 if it

is

false. You can write in-

340

2-11

Language Elements

Logical Operators

The logical operators NOT, AND, OR, XOR, IMP, and EQV are operators that
compare the nth bit
evaluated after the arithmetic and relational operators; therefore, arithmetic expres­sions resolve to a number which
operator test can be used with logical operations.
of

the same precedence in a single expression, they are evaluated left to right. Table

2-6

lists the logical operators in order of precedence'. Some examples

operators, used in complex expressions, are shown below.

String Operator

The relational operators may be used with strings to compare them according to
ASCII order.
to the first
used with strings: the concatenation operator
two

of

argument X with the nth bit

IF

A>=3.5X

IF

B=1

IF

(A-B) AND

or

more strings joined together.

A$ =

B$+C$

OR

X > 3 THEN

OR B=2 OR B=3 THEN

If

part

(B+3)

strings

of

the longer, then the longer

THEN STOP ELSE

of

unequal length are compared, and the shorter

of

argument

is

compared with another number. A relational

If

there are two logical operators

01=0

2750

ELSE

280u

IF

(A AND

is

greater. There

(+).

This operator defines a string

B)

THEN CLOSE 2

is

Y.

They are

of

the logical

is

identical

one operator only

BASIC-SO

as

Expressions

Except for the command and stateqlent instructions, all of the language elements
previously discussed can be combined to form expressions. Depending on the type of
constants, variables, and operators used, expressions can be classed as numeric or
string.

Numeric Expressions

In BASIC-80, numeric expressions are created with numeric variables, constants,
functions, and operators. Variables are initialized with
values with assignment statements, or with

INPUT statements during program

execution.

Any function which returns a numeric value can be used in a numeric expression.
Strings can only be used if they are converted to a number. Numeric expressions can
use arithmetic, logical,

K(I) = B*SOR(X)
IF

A>12.1 THEN C = C + 1

IF PEEK (2FFFH) AND

or

relational operators. Some numeric expressions:

OCH

THEN PRINT

String Expressions

String expressions can be specified in BASIC-80 using string constants, string
variables, relational operators, and the concatenation operator

If

tion operator combines two strings into one.
characters, execution halts and

an

error message

sions are:

A$ =

"NAME:" + NAME$
IF B1$>R$ THEN 81$ =
R$(I)=R$(I) + S$(I) +

""

"DONE"

the resulting string

0, and may be assigned other

"ON"

(+).

The concatena-

is

longer than

is

displayed. Some string expres-

255

2-12

CHAPTER 3

ENTERING

With BASIC-80, you can create new programs by entering statements line by line, or
you can access saved programs from disk storage.
you can use the ISIS-II BASIC-80 Text Editor

RMX/80

The following topics show how to use
ISIS-II BASIC-80 Text Editor to aid program development.

BASIC-80 does not have a Text Editor.

AND

BASIC-80 programming features and the

EDITING PROGRAMS

If

you're using ISIS-II BASIC-80,

to

alter

new

or saved instruction lines.

Entering Instruction Lines

When you invoke BASIC without specifying a file name, there

is

ready

to

The system
sists

of

a line number from 0 to 65529 followed by the language elements (program
statement, constants, variables, operators, functions, etc.).
number alone after a line with that number has been entered with text, that line
deleted.

You can enter statements in any order. To review the statements in a program, use
the

LIST command.

You can have
given increment, by using the
mand,
When you end the statement with a carriage return (CR), it prints the next line
number and again waits. To stop the automatic line numbers, enter a Control-C.

BASIC displays the line number and waits for you to enter the statement.

BASIC-80 provide line numbers, starting

accept commands or program statements. A statement con-

It

displays the statement in numeric order.

AUTO command. After you enter the AUTO com-

is

no program

If

you type a line

at

a given number, with a

to

run.

is

If

AUTO generates a line number that already exists in the program, it prints

asterisk (*) after the line number.

If

the existing statement.
You can use Control-I

is

of each line
Control-I, the cursor or print head moves to the beginning of the next column.

BASIC assumes a width
WIDTH command.

To enter more

If

you want to format the program so that additional statements appear on separate
lines (but are still
(LF) key to move to the beginning
number
doesn't end until you enter CR.

To
BASIC-80 doesn't try to execute such lines,

of

put

a comment in a BASIC-80 'program, enter REM after the line number.

divided into 8-character-wide columns. Each time you press

than

part

times, up to the 255-character line-length limit; the program statement

you enter a Control-C, the existing line

as

a tab key

of

one statement per line, separate each statement with a colon (:).

of

the same numbered program statement), use the Line Feed

If

you enter a statement, what you enter replaces

is

unchanged.

if

you want to format your statements. The width

72

characters. You can change the width with the

of

the next display line. You can do this any

but

they become part

of

the program.

Correcting Entry Errors

If

you make

key

to

pressing CR).

an

error while entering a line, you can correct it by using the RUBOUT

erase characters (as long as you haven't entered the line into memory by

an

3-1

Entering

and

Editing

In the Command Mode, the RUBOUT key deletes the last entered character each
time you press it, and backspaces the cursor on a CRT.

RMX/SO

CR, the program statement

BASIC-SO,

RUBOUT echoes the last-entered character.

is

entered without the rubbed-out characters.

On a teletype, or with

If

you then press

enter new characters and then press CR, the new characters appear in the line.

If

BASIC-SO

you

Suppose you enter 52 instead of 55.To erase the

30

A=8*52 •

30

A=8*5

If

you press RUBOUT again, the 5

30

A=8*

To change

30

A=8*52 •

30

A=8*

30

A=8*37 •

52

•

•

to

37,

press RUBOUT twice, then

•

is

deleted:

2,

press RUBOUT:

3,

7:

When using the Edit Mode, RUBOUT works somewhat differently. Refer to the
Editing

Program Text Section for details.

Control-R displays the line as corrected, still waiting for more input:

30

A--=8xx*522537 (Control-R)
A = 8*37

To cancel a line, simply press Control-X.

Editing Program

Intel ISIS-II
or entire lines. The Editing Mode has its own set
3-1

briefly describes each

terminal beeps and the character

BASIC-SO

Text

has an Editing Mode used to change individual characters,

of

subcommands and syntax. Table

of

the subcommands.

is

ignored.

If

an illegal character

is

entered, the

3-2

Table 3-1.

Function

To delete text:
To insert text:
To

delete all characters to the right of the cursor

and insert
To insert characters at the end of the line:
To search for a character:
To
To change next n characters to y characters:
To restore
To restore original line and restart Edit Mode:
To print balance of line and restart Edit Mode: L
To leave Edit Mode and keep changes:
To

edited
To delete unwanted characters:
To place one logical statement line on two

physical lines:

To leave next n characters unchanged:

text:

delete all characters until specified character:

original line and leave Edit Mode:

leave Edit Mode, keep changes, and print the

line:

BASIC-80Editing Subcommands

or

more

Syntax

[integer] 0

I character [character. .. ]

H character [character ... ]

X character [character ... ]

[integer]
[integer] K character
[integer] C character [character ... ]

Q

A

E

Carriage return

Rubout
Line Feed

[integ.er] space

S character

BASIC-SO

Entering

and

Editing

Complete editing
variables to zero or null.
editing mode with the
BASIC-80 returns

of

a line replaces the old line with the edited line. This resets all

To

end editing without losing prior variable values, exit the

Q subcommand after the line number has been printed.

to

command level, variable values are unchanged

and

any editing

changes are lost.

There are three ways to enter the Editing Mode:

1)

Type

EDIT

line number, and BASIC-80 returns the line number requested.

you press the space bar, the cursor moves

to

the desired location in the instruc-

tion line.

2)

When entering text, type a Control A instead

of

a carriage return. This causes a

carriage return, a space, and the computer prints an exclamation point. The cur-

at

sor points
ing the space bar.
last line,

3)

If

BASIC-80 encounters an instruction line with a syntax error during program

execution, it will halt

the first character

If

and

you

can't

you use CONTROL-A after listing a program, it edits the

change line numbers.

and

print

of

the sequence, and can be advanced by press-

an

error message

of

the format: SYNTAX ER-

ROR IN (line number). Below the error message, the computer returns the line

and

number,

In the Edit Mode, pressing
deleted. Use the D subcommand to delete characters

In the explanatory sections
edited by each subcommand. The

head,

and

all characters are shown as they appear

the line may be edited.

RUBOUT will echo characters,

b~low,

a typical line

"."

,in

the Edit Mode.

of

program text

indicates the position

on

the terminal. Such editing sub-

but

is

of

the cursor

they are

edited and re-

commands as D, L, Carriage Return, Escape, and so on are represented
theses: (CR), (ESC), (D), (4SE) to avoid confusion.

You should

tryout

other examples to gain facility with the editor.

or

in

these

If

not

print

paren-

or

of

In the following sequence
hypothetical program. Line

edit subcommands,

40 returns a syntax error message, since it needs a

PRINT instruction following ELSE,

40

IF

A>B THEN

120

OR

ELSE

and

should not contain OR:

"NULL

SET"

we

will be editing line 40

of

D Subcommand

The D subcommand

counted as characters.
just the remaining characters are deleted. The argument n
to 255, and the default value
backslashes, i.e.,

The syntax

of

[integer] D

In the example below, line 40 returned a SYNTAX ERROR message when the pro­gram ran.

BASIC-SO displays the error message and enters the Edit Mode.
ing the space
incorrect character

40

IF

A>B THEN

40

IF

A>B THEN

The command( 3D) (press 3, then

is

used to delete characters to the right

If

there are less than n characters to the right

is

\characters\

the D subcommand

bar, the text

is

of

line

encountered.

120

OR

ELSE

120.

of

the cursor. Spaces are

of

the cursor,

is

an integer in the range 1

1.

The deleted characters are printed enclosed by

.

is:

By

40

is

displayed character by character until the

"NULL

D)

results in:

SET"

press-

a

40

IF

A>B THEN

120

\OR\

•

3-3

Entering

and

Editing

L Subcommand

BASIC-80

The L subcommand prints the rest
subcommands. The cursor
command

to

display previously edited text and restart editing at the beginning

is

of

the original line, and waits for further editing

to the left

of

the first character. You can use the L sub-

of

the

line:

40

IF

A>B

THEN

40.

120

ELSE

"NULL

SET"

I Subcommand

The I subcommand inserts characters after the last character typed. Each character
typed after typing I

ESCAPE key. To end insertion and leave the Editing Mode, press the Carriage

the
Return key. Characters may be deleted when using the I subcommand by pressing

RUBOUT key.

the
The syntax

of

I character [character] ...

Suppose you want
space bar until you reach the proper point:

40

IF

A>B

and then enter:

(I) PRINT (ESC) (L)

And you
40

IF

A>B

is

inserted

at

the I subcommand

to

insert the word

THEN

120

ELSE.

will see:

THEN

120

ELSE PRINT

the current cursor position. To end insertion, press

is:

"PRINT"

"NULL

into the previous example. Press the

SET"

H Subcommand

The H Subcommand deletes all characters to the right
the insertion mode, like the I Subcommand. When through inserting characters,
enter

(ESC) to end insertion

of

The syntax

H Character[Character] ...

If

you want to change the message

"UNDEFINED

the H subcommand

SET",

or

(CR) to end editing.

is:

"NULL

you can use the H Subcommand to do it. Move the cursor to

the proper point with the space bar:

40

IF

A>B

THEN

120

ELSE PRINT

Enter (H) "UNDEFINED

40

IF

A>B

THEN

120

SET"

(ESC) (L):

ELSE PRINT "UNDEFINED

SET"

of

the cursor, and then enters

in the previous example to

SET"

X Subcommand

The X subcommand prints the rest

of

end
command is used

the line, and enters the insertion mode; as for the I subcommand. This sub-

to

add new text

the insertion mode.

of

the line to be edited, moves the cursor to the

at

the end

of

instruction lines. Execution

is

as in

3-4

BASIC-SO

Entering

and

Editing

The syntax

Returning to the previous example, if you wish to add text

of

the X subcommand is:

X character [character] ...

at

the end

of

the given in-

struction line, use the X subcommand:

40

•

Enter (X)

40

IF

A>B

Enter new

40

IF A >B

THEN

text

THEN

120

ELSE PRINT "UNDEFINED

at

the

cursor-;A;

120

ELSE PRINT "UNDEFINED

B (ESC) (L):

SET"

•

SET";A;

B

S Subcommand

The S subcommand examines characters to the right of the cursor., to find the nth

occurrence
default
searches, printing all characters encountered. When the nth occurrence
fied character
specified character

The syntax

of

the specified character, where n

is

1.

This subcommand skips the first character to the right of the cursor and

is

an integer in the range 1 to 255; the

of

is

found, the cursor stops

is

not found, the cursor stops at the end

of

the S subcommand

is:

at

the character.

If

the nth occurrence of the

of

the line.

the speci-

[integer] S character

The S subcommand can be used with an example to find the nth occurrence

we

specified character. Suppose

"E"

the 3rd letter

40

•

Enter (3SE):

40

IF

A>B

At

this point, the other editing subcommands may be used.

in line 40:

THEN

120

want to move the cursor to the space occupied by

ELSE •

of

the

K Subcommand

The K subcommand functions like the S subcommand except that it deletes all

of

characters passed over until the nth occurrence
deleted characters are enclosed in backslashes.

The syntax

of

the K subcommand

[integer] K character

is:

The K subcommand may be used on our example.

of

P,

1st occurrence

40

•

Enter

and print backslashes:

(1

KP)

the specified character. The

It

will

eliminate all text up to the

\40\

IF

A>B

THEN

Enter (L)

40

PRINT "UNDEFINED

120

ELSE.

SET";A;

B

3-5

Entering

and

Editing

C Subcommand

The C subcommand changes the next n characters to the specified character(s).

of

integer is specified, the character immediately to the right

the cursor

is

changed.

If

BASIC-SO

no

The syntax

of

the C subcommand is:

[integer] C character [character ... ]

In our previous example, line 40 was reduced to:

40

PRINT "UNDEFINED

This can be changed to print

Move

the

cursor to:

40

PRINT.

Enter

(2C)

RE

(L)

40

PRINT "REDEFINED

40

•

SET";A;

"REDEFINED

SET";

8

A;8

SET"

with C:

Q Subcommand

The Q subcommand restores the original line, as it was prior to editing,

the editing mode. Note

This subcommand returns the user

edited command. This subcommand only works when editing program lines.

that

if

an

instruction

to

is

edited with Q, the changes are lost.

the command mode without executing an

and

leaves

A Subcommand

The A subcommand restores the original line and prints the original line number

is

below. Editing
lines.

When the A subcommand

40

PRINT "UNDEFINED

restarted. This subcommand only works when editing program

is

used with the previous example, the result

is:

SET".
Enter (A) (L)
40

IF

A>B THEN

120

ELSE

"NULL

SET"

40.

E Subcommand

The E subcommand exits the editing mode. The edited line replaces the original line.
When the E subcommand

40

PRINT "UNDEFINED SET"

(The E subcommand is entered)

Carriage

A Carriage Return exits the editing mode,
The edited line replaces the original line.

Return

is

used with the previous example, the result

and

prints

the rest

of

the line being edited.

is:

3-6

CHAPTER 4

ERROR

If

you enter improper instructions, syntax, or formats, BASIC-80 issues an error
message. This chapter explains what these errors mean, how they may be trapped
with the ON ERROR statement and pinpointed with the TRON, TROFF, ERR, and
ERL instructions, and how errors may be simulated with the ERROR statement.

HANDLING

BASIC-80 Error Messages

When BASIC-80 encounters an error in a program, it displays an error message.
Appendix A lists the error messages and error codes, and describes their meaning.
These errors stop program execution. You can use the
to correct obvious errors, add error-trapping instructions, or use the trace facility.

Syntax

If

message, and enters the Edit Mode:

Error

BASIC-80 detects a syntax error,

10

LET

20

PRINT A
RUN
SYNTAX ERROR
10

•

Messages

A=

IN

10

it

stops program execution, displays an error

BASIC-80 editor at this point

You can now change line 10, as described in Chapter
without making any changes, and to preserve the variable values in the program,

Q.

If

type
variable values are lost.

you enter any other editing subcommands (including Carriage Return)

3.

To leave the Edit Mode

Overflow, Underflow, and Divide-by-Zero

In BASIC-80, the single- and double-precision floating-point overflow, underflow,
and divide-by-zero errors do not halt program execution.

Overflow. Single-precision floating-point overflow occurs when the magnitude of a

(±)

single-precision numeric value exceeds
floating-point overflow occurs when the magnitude

(±)

E20*1

D200*1

1.79 x

E20

D200

1.79769313486231

value exceeds
generated, the message OVERFLOW
ble magnitude for the given representation with the appropriate sign

ex~cution

The following examples show single- and double-precision overflow:

proceeds.

10

A = 1

20

D#

= 1

30

PRINT A;D#

RUN

OVERFLOW
OVERFLOW

3.402824E + 38

308

10

(1.79D308). When a value of this magnitude

3.4 x

is

displayed, a value equal to the largest possi-

D +

308

38

10

(3.4E38). Double-precision

of

a double-precision numeric

is

assigned, and

is

4-1

Error

Handling

BASIC-SO

Underflow. Single-precision floating-point underflow occurs when the magnitude

of

a single-precision numeric value

precision floating-point underflow occurs when the magnitude of a double-

is

precision numeric value

is

magnitude

generated, no message

less

than

is

less than

(±)

2.2 x

is

printed, the result

10-

(±)

308

1.2 x

(2.2D-308). When a value of this

10-

is

defined

38

(1.2E-38). Double-

as

zero, and pro-

gram execution continues.

is

Divide-By-Zero. Divide-by-zero
precision overflow protocol, except that the message printed

Integer

Operations

handled identically to single- and double-

is

DIVIDE-BY -ZERO.

Integer overflow and division by zero are treated as normal errors. Program execu­tion halts. Integer overflow occurs when a value greater than 32767.49 or less than

is

-32768.49

Error

converted to integer representation. Integer underflow cannot occur.

Trapping

Error trapping allows you to trap and correct errors. Errors normally halt program

is

execution and return error messages. When given before an error

encountered, the
ON ERROR GOTO statement transfers program execution to a specified line
number when an error occurs, and suppresses any error messages other than those
you specify and write yourself.
specified location to identify and correct errors. In the following example, when
is

entered in response to the INPUT statement, an error occurs and the user-written

You can write an error-service routine at the

-3

error message displays:

10

ON ERROR GOTO

20

INPUT A

30

PRINT SQR{A)

40

GOTO
100
110
120

RUN

20
PRINT
PRINT
RESUME NEXT

"ARGUMENT
"ENTER

100

NEW

CANNOT
VALUE."

BE

NEGATIVE."

? 3

1.732051

?

-3

ARGUMENT CANNOT
ENTER NEW

VALUE

BE

NEGATIVE

?

Suppose there

is

no error routine (made up of lines

10,

100,

110,

and

120)

in

the

above example, and you wish to identify this particular error. The ERR and ERL

A)

functions return the error code number (see Appendix

error occurs in, respectively. In this way, you can identify the kind

and the line number the

of

error and the
line it occurs in and write individual error handling routines for individual errors.
The program below uses ERL and ERR to identify the location and nature of any
error.

In the following example, the
routine at line

100, which identifies one specific error (division by zero) and the line

ON ERROR statement enables the error-service

number in which it occurs:

4-2