BBC Basic and Beyond
Familiar to millions
The BBC shipped with what many still
consider to be a superb example of the Basic programming language: BBC Basic.
Certainly most people who used a BBC at home would have at least dabbled with
the language, after all the sizeable user guide supplied with the machine, over
500 pages, was devoted nearly exclusively to the programming of the machine.
Now a warning, there's some serious technobabble coming up and while I'm not
going to start talking about strange particles and making up peculiar words
this could still act as a mind numbing sedative for some. Do you consider
yourself suitably warned? Good, read on :)
In contrast to many other variants of Basic of the time BBC Basic supported
well organised structured programming through its rich support for function
calls and procedures and local and global variables. In contrast many other
variants of Basic forced the programmer to construct a spiders web of GOTO
statements and peculiarly named global variables.
Type it in!
Ooo a pretty picture
Its frightening to consider how many UK
programmers working today first cut there teeth with a program like the one on
the left. Which incidentally produces the output on the right. Oh and if your
looking to get it easy and paste the program on the left into your emulator:
forget it. I had to type the damn thing in and I wouldn't want to deprive you
of that truly magical feeling of typing it in from a printed listing only to
find there's a bug in the code. One final notable feature of BBC Basic was its
built in assembler. Using it you could enter the mnemonics of 6502 assembly
code and improve the performance of your Basic apps where appropraite or write
pure assembly programs.
When writing your games, errr I mean programs, you had a number of different
graphic modes to choose from: the Model B supported a total of 8 graphics modes
while the Model A featured only a subset of those modes due to memory
limitations. For each it was possible to select the colours to use from
a total palette of 16 colours, however 8 of those were 'flashing' colours
and there were no flesh tones. Due to this many BBC games had a rather bright
feel to them! The modes available to the programmer were as follows.
| Mode |
Text Resolution |
Graphics Resolution |
Colours |
| 0 |
80x32 |
640x256 |
2 |
| 1 |
40x32 |
320x256 |
4 |
| 2 |
20x32 |
160x256 |
16 |
| 3 |
80x25 |
N/A |
2 |
| 4 |
40x32 |
320x256 |
2 |
| 5 |
20x32 |
160x256 |
4 |
| 6 |
40x25 |
N/A |
2 |
| 7 |
40x25 |
Teletext |
Teletext |
The memory for the graphics mode selected came out of the machines 32k of RAM
and as such choice of mode was always a compromise between resolution and
colour depth. With its low resolution and medium number of colours mode 5 was
very popular among game developers as it left a reasonable amount of space for
the game program itself while still allowing a reasonable number of colours.
Modes 0 and 7 are also worth special mention: mode 0 for its high resolution
and mode 7 as it enabled Teletext style screens to be displayed and took very
little memory. And yes, thats the very same Teletext still viewable on
television today.
And with that I'll leave programming the Beeb and move onto what everyone is
really interested in: did it have any great games?
