PROGRAM PITSTOP
Your Sinclair, February 1992

All JONATHAN DAVIES ever wanted was a Barbie-mobile. He didn't get one this
year, so he's living in hope. Meanwhile, he'll make do with a few lists ...

If you're a Spectrum owner who likes living life in the fast lane, who
seeks the adrenalin-pumping thrills that only typing in listings can
provide, who wants to be a hit at parties and attract lots of members
of the opposite sex, you've turned to the right page.

And boy, have I got a line-up for you this month. (I had to check
twice, but I have.) For starters there's - wait for it - a message
scroller from Andrew Hunt. Then there's - gasp - a musical program
from Darren Bloggs. And finally - swoon - a "patch" for Draw It, your
YS art utility.

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ROCK AND SCROLL
by Andrew Hunt

[I've corrected a couple of bugs that were in the original version.  ]
[The subroutine at 65131 copied one too many bytes on each iteration,]
[causing the left-most column to get copied to the right-most column ]
[before the next column is scrolled in.                              ]
[The subroutine at 65180 copied one too many bytes when resetting the]
[attributes, overwriting the first byte of the printer buffer and so ]
[causing a crash if run on the 128K.                                 ]
[I've done a corrected version in ROCKSCRL.TAP "RockSfix.o".     JimG]

[NOTE: Enough space must be CLEARed below 65000 to make room for the ]
[messages.                                                       JimG]

I'm afraid your eyes don't deceive you: here's yet another message
scroller. "But why?" you cry. "We've been faithfully typing in Pitstop
scrollers for years, and we're up to our nostrils in the things. Our
eyes have developed a permanent list to the left from watching
messages scroll past. The last, the very last, thing we want right now
is another scroller. Take it away. Cast it thither."

But have patience, please. Andrew Hunt's scroller is different. Okay,
it's not that different, but it is remarkably short. It also scrolls
messages which are a whole screen high, exceedingly smoothly and in a
colour of your choosing. You can't say fairer than that.

Getting the thing up and running shouldn't take long. Just type in the
BASIC section and save it with SAVE "scroller" LINE 9999. Then turf
out a copy of the Hexloader from a previous YS and use it to enter the
hex section. Save that as "code". Then reload and run.

Most of the BASIC listing is taken up by a demo, and an explanation of
how it works. That saves me having to go through it all, as you should
be able to work out how to replace Mark's message with your own
without any trouble at all.

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TUNES
by Darren Bloggs

Pitstop is many things, but it tends to be a bit quiet. So I thought
I'd liven it up a bit with a little music. I wouldn't normally print
huge listings containing nothing but PLAY commands [Although the PLAY
commands weren't actually printed in the listing. JimG], as they're
incredibly boring to type in (even by Pitstop's standards) and a
nightmare to debug. But I think you'll find that this one's a cut
above the rest, and just the job for impressing Granny when she points
at your Spectrum and says: "But what does it actually do?"

To get it working you've just got to type it in and run it, although
you might want to save it first just in case. I'd better point out,
however, that the program will only work on 128K Spectrums.

It'll play three tunes, but I'm not telling you what they are. (The
first person to write in and tell me who wrote them can have, erm, a
pat on the back.)

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DRAW IT - AN ASIDE
by Katherine Bostock

Draw It, which came sellotaped to the front of your November YS, is a
pretty cool program, but suffers from the rather spook problem that
128K Spectrum owners have to leave their tape players playing while
using it. Katherine Bostock was especially annoyed by this, and not
only worked out what was causing the problem but how to fix it as
well. What a star.

The difficulty apparently arises because "The compiler used to
generate the code assumes that bit 6 of port FE ..."

Er, let's jump straight to the solution, eh?
+ Firstly, type MERGE "" and load the first part of the program.
+ Save this onto a fresh tape by typing SAVE "DRAWIT" LINE 1.
+ Type NEW, and then CLEAR 24659.
+ Then LOAD "" CODE 30000 and restart the original tape.
+ When the first section of code has loaded, type SAVE "DRAWN" CODE 30000,6912
  to save the loading screen onto your new tape.
+ Then go back to the covertape and LOAD "" CODE to load the main block of code.
  (I hope you're still with me.)
+ Next, type in the listing below and run it. It'll take ages, but when it's
  finished you'll be able to type SAVE "DRAWCODE" CODE 24660,40876 to save a
  new copy of Draw It that'll work on any Spectrum without all that nonsense
  with the tape player.

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FIN
Thanks to everyone who sent in programs this month, and thanks in advance if
you're planning to send me something for the next issue. If you are, pop it
onto a tape and send it to Program Pitstop, Your Sinclair, 30 Monmouth Street,
Bath BA1 2BW.
