www.riscos.com Technical Support: BBC BASIC Reference Manual

BBC BASIC Reference Manual

Part 1 - Overview 1

1. About this Manual

Intended readership

Structure of the manual

Conventions used in this manual

2. About BBC BASIC

What is BASIC VI?

Why use BASIC VI?

The BASIC interpreter

Window managed programs

Part 2 - Programming techniques 9

3. Command mode

Entering BASIC

Leaving BASIC

Command mode

4. Simple programming

Entering a program

Altering a program

Deleting whole programs

Numbering lines in a program

Listing long programs

Comments

Multiple statements

Saving and recalling programs

5. Variables and expressions

Types of variables

6. Numeric variables

Integers and floating point numbers

Special integer variables

Arithmetic operators

7. Bases

Hexadecimal numbers

Binary numbers and bits

Shift operators

AND, OR and EOR

TRUE and FALSE

8. String variables

Assigning values to string variables

Joining strings together

Splitting strings

How characters are represented

Converting between strings and numbers

9. Arrays

The DIM statement

Two dimensional arrays

Finding the size of an array

Operating on whole arrays

Array operations

10. Outputting text

Print formatting

The text cursor

Defining your own characters

11. Inputting data

Inputting data from the keyboard

Including data as part of a program

Programming the keyboard

Using the mouse in programs

Programming function keys

12. Control statements

IF... THEN... ELSE

Operators

IF... THEN... ELSE... ENDIF

FOR... NEXT

REPEAT... UNTIL

WHILE... ENDWHILE

CASE... OF... WHEN... OTHERWISE... ENDCASE

GOTO

GOSUB... RETURN

ON... GOTO/GOSUB

For example:

13. Procedures and functions

Defining and calling procedures

Parameters and local variables

ON... PROC

Recursive procedures

Functions

Function and procedure libraries

14. Data and command files

Data files

Writing or reading single bytes

Writing or reading ASCII strings

Command files

15. Screen modes

Changing screen modes

Shadow modes

Text size

Graphics resolution

Colour modes

Changing colours

Changing the colour palette

256-colour modes

Using the screen under the Wimp

16. Simple graphics

The graphics screen

The point command

The line command

Rectangle and rectangle fill

Circle and circle fill

Ellipse and ellipse fill

Graphics colours

The graphics cursor

Relative coordinates and BY

Printing text at the graphics cursor

17. Complex graphics

Plotting simple lines

Ellipses

Arcs

Sectors

Segments

18. Graphic patterns

Default patterns

Plotting using pattern fills

Defining your own patterns

Native mode patterns

BBC Master mode patterns

Giant patterns

Simple patterns

Flood-fills

Copying and moving

19. Viewports

Text viewports

Graphics viewports

20. Sprites

Loading a user sprite

Plotting a user sprite

21. Teletext mode

Coloured text

Making text flash

Double-height text

Changing the background colour

Teletext graphics

22. Sound

Activating the sound system

Selecting sound channels

Allocating a wave-form to each voice

Setting the stereo position

Creating a note

Synchronising the channels

Finding the value of the current beat

Finding the current tempo

Executing a sound on a beat

23. Accessing memory locations

Reserving a block of memory

The '?' indirection operator

The '!' indirection operator

The '|' indirection operator

The '$' indirection operator

24. Error handling and debugging

Generating errors

External errors

Local error handling

Debugging

25. VDU control

26. Editing BASIC files

Editing BASIC files under RISC OS 3

Editing BASIC files under RISC OS 2

Part 3 - Keywords

27. Keywords

ABS

ACS

ADVAL

AND

APPEND

ASC

ASN

ATN

AUTO

BEAT

BEATS

BGET #

BPUT #

BY

CALL

VARIND

STOREA

STSTORE

LVBLNK

CREATE

EXPR

MATCH

TOKENADDR

FSTA

FLDA

FADD/FMUL

FSUB/FDIV

FLOAT

FIX

FSQRT

CASE

CHAIN

CHR$

CIRCLE

CLEAR

CLG

CLOSE #

CLS

COLOUR (COLOR)

COS

COUNT

CRUNCH

DATA

DEF

DEG

DELETE

DIM

DIV

DRAW

EDIT

ELLIPSE

ELSE

END

ENDCASE

ENDIF

ENDPROC

ENDWHILE

EOF #

EOR

ERL

ERR

ERROR

EVAL

EXP

EXT#

FALSE

FILL

FN

FOR

GCOL

GET

GET$#

GET$

GOSUB

GOTO

HELP

HIMEM

IF

INKEY

INKEY$

INPUT

INPUT LINE

INPUT#

INSTALL

INSTR

INT

LEFT$

LEN

LET

LIBRARY

LINE

LINE INPUT

LIST

LISTO

LN

LOAD

LOCAL

LOG

LOMEM

LVAR

MID$

MOD

MODE

MOUSE

MOVE

NEW

NEXT

NOT

OF

OFF

OLD

ON

ON ERROR

OPENIN

OPENOUT

OPENUP

OR

ORIGIN

OSCLI

OTHERWISE

PAGE

PI

PLOT

POINT

POINT

POS

PRINT

PRINT#

PROC

PTR#

QUIT

RAD

READ

RECTANGLE

REM

RENUMBER

REPEAT

REPORT

REPORT$

RESTORE

RESTORE ERROR

RETURN

RIGHT$

RND

RUN

SAVE

SGN

SIN

SOUND

SPC

SQR

STEREO

STOP

STR$

STRING$

SUM

SUMLEN

SWAP

SYS

TAB

TAN

TEMPO

TEXTLOAD

TEXTSAVE

THEN

TIME

TIME$

TINT

TOP

TRACE

TRUE

TWIN

UNTIL

USR

VAL

VDU

VOICES

VPOS

WAIT

WHEN

WHILE

WIDTH

BBC/Master compatible calls

Formatting numbers

Part 4 - Appendixes

28. Appendix A - Numeric implementation

Numeric types

Effects of storage size

What is floating point arithmetic?

Implementation

29. Appendix B - Minimum abbreviations

30. Appendix C - Error messages

31. Appendix D - Inkey values

32. Appendix E - Colour modes

33. Appendix F - Plot codes

34. Appendix G - VDU commands

35. Appendix H - *FX commands

36. Appendix I - BBC BASIC's history

BASIC II improvements

BASIC III improvements

BASIC IV improvements

BASIC V version 1.04 improvements

BASIC V version 1.05 improvements

BASIC VI version 1.05 improvements

37. Appendix J - ARM assembler

Using the BASIC assembler

Saving machine code to file

Executing a machine code program

Format of assembly language statements

Registers

Condition codes

The instruction set