PROGRAM PITSTOP
Your Sinclair, March 1990

Snap, crackle and pop, Pitstop's got the lot With silly names and fun
and games, and a bloke who looks like a cop. (And his name is Jonathan
Davies.) Hurrah!

[Both of the hex dumps in this month's article had the last line  ]
[missing. I managed to work out the missing bytes for MLD Caspersz]
[coloured blocks program, but gave up on Memolook.                ]
[(YS never printed corrections for either of them.)           JimG]

[Correction for Memolook supplied by "Bad Beard" (Jan.2008).  JimG]

Influenza, eh? It's a messy business, and I seem to be its latest
victim. That's made sifting through the tapes a little tricky, what
with huge pools of gunge flowing everywhere, apocalyptic coughing fits
every ten seconds and a headache that you can hear from the next
office. What's more, my last handkerchief was last seen staggering out
of the door waving a white flag, so my sleeve is having to bear the
brunt of things at the moment.

Still, I've managed to prop my bloodshot eyes open for long enough to
take a butchers at this month's crop of proggies, so let's see what
we've got.

Right, among this month's delightful contributors is Andras Hirschler
who's written a brilliant program for printing loads of dots on the
screen. Then a bit of light entertainment from Sean Sanderson.
(Someone may find a use for it.) MLD Caspersz also puts in an
appearance with a couple of interesting thingies. And lastly Alex J
Chircop presents another sound-to-light program.

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MEMOLOOK
by Andras Hirschler
from Your Sinclair, March 1990

[Unfortunately, five bytes were missed off the hex dump for this  ]
[program, so it crashes. No correction was ever printed. As I     ]
[didn't realise this until I'd typed it all in, I decided that I  ]
[might as well include it anyway.                             JimG]

[Correction for Memolook supplied by "Bad Beard" (Jan.2008).  JimG]
$5bf8   e1       pop   hl
$5bf9   c1       pop   bc
$5bfa   10 cb    djnz $5bc7
$5bfc   c9       ret

RAM's a funny thing. It comes in very handy, of course, but you're 
never quite sure how it's all arranged and where all the important
bits are at any given moment. Not any more though. Andras Hirschler
has the answer, and what's more he's from Hungary, making this my
first program from, you know, over there.

Memolook (good name) performs the astonishingly useful function of
drawing a map of your Speccy's memory on the screen. It does this by
putting in a black dot every time it encounters a non-zero byte. By
the time it's finished (it only takes a second) you'll be able to see
exactly which parts of memory have got interesting stuff in and which
are just blank. Very useful for hackers and the like.

To extend the possibilities even further Memolook features a little
cursor which can be moved around with Q, A, O and P. The address the
cursor is on and the value in that address are displayed continuously
in the top left-hand corner of the screen. Space returns to Basic.

To get it going, type in the Basic part first and save it. Then, using
the Hex Loader, type in the hex and save it after the Basic. (When you
get to the bottom of the hex, press Symbol Shift and A.) The program
features a super-dooper demo routine so you can see exactly what it does.

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"ER, THINGY"
MULTI-COLOURED SCROLL
by Sean Sanderson

Continuing this issue's theme of programs that appear completely
useless until one day you find a use for them (by which time you've
forgotten where on earth you saw them in the first place), Sean
Sanderson sends us this. It's a kind of multi-coloured scrolly thing,
the finer details of which I'll leave you to discover. It's
ultra-short, especially once you've chopped out the REMs, but the
results are quite surprising. (Only 'quite', mind.)

Actually, I think Sean's real reason for writing in was to try to get
in a plug for the Spectrum Music Club which he runs. It covers
everything to do with Spectrum music, with emphasis on the Music
Machine, and his phone number is 05242 62258 evenings and weekends.
Good job I can't be bought that easily.

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A COUPLE OF THINGS
by M.L.D. Caspersz

[The missing bytes at the end of the coloured block hex dump were:]
[0D 20 F2 C9                                                  JimG]

Here are a couple of programs from MLD Caspersz who not only lives in
Sri Lanka but has also written a book (this section seems to have more
plugs in it than, er, something with a lot of plugs). The book looks
rather good actually (it's called Maturing In Machine Code), as can be
seen by the following two programs from it.

The first performs the simple function of printing big coloured blocks
on the screen, and is notable because a) it's blimmin' fast and b) it
makes interesting use of DEF FN (some people might think so, anyway).
Type in the Basic, save it, type in the hex with the Hex Loader, save
that too, run it and hold down a key to print blocks.

Secondly there's a magic square program. Well, two actually. They
print, funnily enough, magic squares. And why are they magic? They
aren't actually, but you'll find that all the rows and columns add up
to the same number. A bit of a mathematical phenomenon really. The
first is the better presented, but the second one does the whole thing
in one line (with a bit of cheating).

[Note that these magic square programs only work for ODD numbers.  JimG]

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SORT OF FLASHY THING
by Alex J Chircop

[a$ wasn't initialised, so the program crashed straight away. Lines 20&30]
[in the listing just LET a$=" ", so the screen was blank all the time.   ]
[YS used a printer which didn't print UDGs, so maybe that's why. I put in]
[a couple of symbols so that something was visible.                  JimG]

Sound-to-light programs are nothing new, but seeing as there are loads
of different things you can do with them I thought I'd print another
one. This time it's from Alex J Chircop who, in addition to making
impressive use of his middle initial, lives in Malta which is, erm,
miles away.

This particular sound-to-light program works a bit like an
oscilloscope (one of those things that draws wibbly lines). Bash it
in, play some music or something through the ear socket and off you go.

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ERRATA
I'm informed by Ken Taylor (who, funnily enough, lives just down the
road from me. Hilarious, eh?) that the Toolkit program in the
September YS is a bit dodgy when dealing with array variables. This
shouldn't cause too many problems, but just to be on the safe side Ken
supplies the following POKEs to cure the problem once and for all -
64915,205  64963,0    64967,35
64916,194  64964,0    64968,35
64917,253  64965,35   64969,201
64962,17   64966,94

So ...
... that's it, really. Having typed that lot in you'll probably be
bursting with inspiration, so send whatever you come up with, on a
tape, to me, Jonathan Davies, at Program Pitstop, YS, 14 Rathbone
Place, London W1P 1DE. One idea I've been toying with is a Speccy
keyboard buffer that stores up key presses and releases them at a
speed that the basic editor can handle. See what you can do.
