Your Spectrum
Issue 19, October 1985 - Letters Page
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C'mon you lot! Either Bobby Charlton or you lot on YS know sweet FA (geddit!) about a football pitch.
Just read this from Frontlines, issue 17: "There's a lot more to it than shooting from the sixty yard line." Anyone who can shoot from the sixty yard line, should be playing for East Fife or locked up!
Are you still playing Subbuteo? Or have you made what's commonly known as a footballs up?
D Leitch
Leven, Fife

After a quick show of hands in the changing rooms, we couldn't produce even one footie fanatic on the team. So, what's wrong with a sixty yard line and why do they only have them in East Fife? In fact, the last time the Ed put on a pair of shorts, he was arrested for indecent exposure! Not that there's anything wrong with his knees that amputation wouldn't cure. Troubleshootin' Pete


Pssst ... After doing a little sniffing around, I sussed out that the following games are due for release in the very near future. So, look out for Dun Nothin', Manic Mooner, Spotty Pidgeon, Monty Birthmark, Spy vs Spy Hunter, Anne Droid Three, Swan Vesta Day and Kosmic Kanga's Jump Challenge. Check 'em out!
G A D Shaw
Barnsley, S Yorks.

Ummm, I'd very much like to know who your source is, 'cos our spies have only told us of You're Welcome to the Frankie Drone, Dimbusters, and The Choccy Horror Show (a tale of marauding Mars Bars). If anyone else has further information, you know where to send it - elsewhere! Troubleshootin' Pete (the other Shaw on this mag!)
How many times have I told you to stop members of your family from sending us silly letters? Will this bid by the Shaw clan for global supremacy never cease? Ed
f o r u m

The writing's on the wall. Just peel it off and send it to Forum, Your Spectrum, 14 Rathbone Place, London W1P 1DE. And there's a bundle of free software waiting for this month's Star Letter!

Now that we can have up to 16 interrupt routines running at once this is a golden opportunity to include Toni's Machine Code Breakout in YS issue 1. It's amazing what this routine does with so few bytes, and it's even shorter when adapted for Interrupt Manager.
David Roberts
London SE4

Phew, thank goodness you stopped when you did or you'd have written it so it appeared every time you sneezed! Nice one, Dave. Troubleshootin' Pete.


I'm desperate ... I can't load long programs properly on the microdrives I bought last April in England. I knew Uncle Clive's microdrives weren't perfect but I didn't think they could be this bad. In fact, programs load OK for a week or so and then when I need to use them again, I get the 'file not found' error message. The four freebie cartridges work without problems. Perhaps there's something wrong in the saving procedure? Perhaps it's the cartridges, I don't know. Can you help?
Veuillez agreer l'expression de mes sentiments distingues et devoues.
Olivier le Roy
Murs-Erigne, France

Sacre bleu. La plume de ma tante. Brigitte Bardot. (That's enough French for one issue, thank-you. Ed). This is the classic problem. For openers, if the drives have been playing up since you first bought them, then it's a good idea to send them back where they came from for a replacement. But if this is a fault that's developed over a period of time, then it could be down to a number of things. First, check that the cable between the Interface 1 and the microdrive looks OK

Star Letter

A while ago, I wanted to plan a screen of output but found that I'd run out of grid paper, so I knocked out a bit of code to produce a grid. Calling it from Basic, every time I needed it was a pain, so I put it into an Interrupt service routine. The original grid was a solid affair and took an eternity to do, so I added a flag system that caused a grid to be produced every other interrupt. Basic was still being deprived of time so I altered the grid to dots as opposed to lines. A means of switching the grid on and off without recourse to the USR call also helped and I've used this final version ever since.
YS August ish saw Toni Baker back with a beaut'. Right, what's the Grid Routine going to say about being called every four or five interrupts or whatever. It didn't mind one bit and casting modesty to the wind I reckon Toni's Interrupt Manager has elevated the humble grid routine to a level worthy of fellow YS fans.
In Toni's Interrupt Table, the Flags bytes don't use the five most significant bits, but if they were to be used and any one or more was high, just prior to checking which ROM is current, a crash may occur - so I suggest inserting the following just before the accumulator is loaded with the first byte of ROM.
AND 3 has been used to mask 6 bits since the C register is subjected to a right arithmetic shift a little earlier. The Grid Routine uses bit 7 of Flags, and only produces a grid when it's high. It also calls upon good services of the Spectrum ROM, so for Interface 1 owners (yours truly not included - I'm too poor), bit 2 and bit 1 of Flags should always read 01.
To get the routine running, place the address of Grid in the Manager Table. Use a Counter and Priority value of, say, 5 to get a feel to start with. The value of Priority will
depend on what use you put the grid to. With regard to. flags, the value should be 3, that is activated but no grid.
Ok, so where's the flaming grid? I hear you ask (or words to that effect). Press the space key and G together (still nothing) and let go - one grid. The grid will go away again once you've pressed the Space/G key combination again.

[see assembler listing below]


and move it about till you've got the best position for the connection. Also, move the Speccy system as far away from the TV/Monitor as possible. If all this fails, bring out the Kleenex and break down yourself for the evening. Troubleshootin' Pete


I've done it! I've finally discovered a mag that doesn't ignore microdrives. (And what took you so long may I ask? Ed). But there's still room for improvement - why don't you have a section each month devoted to the little black boxes. As a newcomer to them, I'd find the hints 'n' tips very useful. (My, you are behind the times. What d'you think Andy Pennell's up to in his new column? Ed).
One more thing. In Forum, issue 13, 'Someone POKEd Pete' with the following suggestion for changing line zero to another line and vice- versa - POKE (PEEK 23535+256+PEEK 23636)+1,X. Well, correct me if I'm wrong but doesn't POKE 23756,x do exactly the same thing with less strain on the old fingers?
Paulo C
Coimbra, Portugal

Nope, you're not wrong but then again you're not wholly right either. It all depends on whether you've got the Interface 1 connected. This is something a lot of POKErs forget when coming up with these quickie solutions. Troubleshootin' Pete.


I'd really like to know how to start a Spectrum club in my area. What activities should we plan and how do we raise funds? Has anybody got any tips?
Cathal Curtis
Carlow, Ireland

Well, Cathal the simplest method if you're still at school or college is to form your club there. Ask a teacher or tutor if they'd be interested in helping you. If you've left the blackboard jungle behind you, then it's an idea to try the local library. They usually have back rooms where you can meet with your machines and it's a good place to pin up notices. Of course, if you're a group of adults, why not meet at the local pub once a week. Once you've marked out your meeting place, it's just a question of drumming up the membership. Send out press
releases to all the computer mags and to your local paper. Advertising in local newsagents will also bring in a few newcomers. After that, word of mouth will do the trick. Of course, if anyone in Carlow wants to get in touch with Cathal, we'd be happy to pass on your letter. Troubleshootin' Pete


How could you call A View To A Kill a megagame. I bought the game and can only sum it up as megagarbage. I was appalled by the pathetic graphics and there were more bugs than in the office of the KGB. I kid you not, my first attempt at games writing was almost as good as this. When the Paris Chase quickly drove me into the second program, I found things a little better but really the duck shoot stop- start system just slows the whole game down. The only exciting thing about the Silicon Mine game was watching Bond tumble all over the place suffering multiple injuries and then making an amazing recovery after scratching his nut.
Come on YS! - Megagame! Were you bribed or were you just maintaining your chances of getting OBEs. (Mmmm, Troubleshootin' Pete OBE. It has a sort of ring to it! TP). I'm sure even Bond himself would have preferred the game to stay Top Secret.
But apart from this, I think the magazine is mega fantastic (crawl, crawl) and I hope this minor criticism won't prevent you from publishing my letter (grovel, grovel).
Scott Murdoch
Linwood, Renfrewshire

Don't think you can get round me like that. How dare you! You accuse me of being bribed and then expect me to publish this terrible tirade against my integrity.
Well, let me tell you, it was only the fiver you slipped in at the last minute that persuaded me to relent. Ho hum.
And c'mon let's not be modest - you've got to admit our review was much better than the game itself! Ed


Ha, a real nail in the coffin for Kevin Cox-up here, unless TP's got a st..stutter. Anyone read From The Hip, issue 17 lately? Well, I quote: "Got that? Well, let's say that you've stuck your routine at 50175 - and you've stuck
your routine at 50175 - and you've remembered to clear up (shouldn't that be down?) to 50175 haven't you?" Notice how it's been taken beautifully out of context to make TP look stupid - not that he needs it!
Plus, am I blind or are you getting mega-stingy on your free software? I can't see a star letter in sight. Phew! If all that doesn't deserve a trainspotter award, what does? (You can find out at the bottom of the page! Ed) So gimme!
Ian Fisher
Barbourne, Worcester, Ian we ain't getting stingy but we're making an exception in your case - you're getting nowt! Troubleshootin' Pete.


I read your rave review of the Mirage Microdriver in the August issue with interest. Did you know that it doesn't work with all Spectrums? - you don't seem to be aware of the fact and Mirage very conveniently forget to mention it in their adverts.
I'll agree that I had no trouble getting my money back when I returned the Microdriver but Mirage denied all responsibility for a fault that'd developed on my Interface 1 after attempting to use the Microdriver.
W Sawyer
Leigh on Sea, Essex

Right, Mr Sawyer, we had a chat with Mirage about your problem and it seems that the Microdriver doesn't work with late issue 1 and early issue 2 Speccies. That particular batch
had a fault in the clock - something Sinclair Research owns up to in their service manuals. It's even cured automatically whenever one of the offending machines goes in for an overhaul. Mirage is now putting a note into the instructions explaining the problem.
Mirage won't take the blame for your Interface 1 troubles, though. The Microdriver is an unpowered unit, so Mirage reckons there's no way it could blow up your Interface I unless you unplugged it while the system was switched on. Troubleshootin' Pete.


I rushed home with ish 16 and typed in 3D Daze from Mr MegaBasic, Mike Leaman. But when I put in the checksum it went berserk. A little bit of detective work pinned the problem on the Hex Loader - Z has been assigned to the loop in lines 50-70 as well as to the start address in line 25. So, instead of the checksum starting at 64000, the start address, it began where the loop finished, coughing up a total of about 200,000.
So, how'd you solve it, I hear you ask. (How'd you solve it? Ed). Just assign a different variable to the loop in lines 50-70 instead of Z - such as M, that's how!
Tuhin Goswami

Drat, you spotted the deliberate mistake thrown in just so you wouldn't think we were perfect. What d'you mean, worra lorra waffle? Oh well Ed.

Trainspotter cartoon
Well, what a silly witty Burger, Tony 'Slim' Samuels is. Take a look at The Generation Game in issue 17. So, the sound on HURG is worth a double cheeseburger, is it?
He sounds - 'scuse the pun - (That's OK, we didn't notice it. Ed) like the kind of daft Burger who writes music programs on the ZX81! (You mean you've never heard his famous rendition of the Sounds of Silence? Ed)
Just for the record, and a
mustard stained Trainspotter's Award, there ain't no sound on HURG. Well, if there is, I've not come across it yet ...
M Sleight
Doncaster, S Yorks

Sounds as though our Tone was too busy chompin' at the cheeseburgers - well just the sound of eating is music to his ears. Don't worry though, it won't happen again. Another slip-up and we'll be stopping his luncheon vouchers. Ed.

; Points to IR FLAGS
       LD   A,#7F
       IN   A,(#FE)
       RRA  ; Space key?
       JR   C,GD_ON?;Nope
       LD   A,#FD
       IN   A,(#FE)
       BIT  4,A ; G key?
       JR   NZ,GD_ON?;No
       LD   A,(DE)
       XOR  #80
       LD   (DE),A
; Space/G keys flips bit 7
; Wait until k'bd is free
  otherwise I'll flip bit
  7 again, and again,....
GD_ON? LD   A,(DE)
       RET  NC ; Grid is
not required so I'm off
back to MANAGER
; Produce Grid (28 ms of
  sheer bliss)
       LD   HL,#4000
       LD   BC,#AA
       LD   D,3
SECT   LD   E,3
       OR   C
       LD   (HL),A
       INC  L
       INC  H
FILL   SET  7,(HL)
       INC  L
       DJNZ FILL
       INC  H
       DEC  E
       JR   NZ,VERT
       INC  H
       DEC  D
       JR   NZ,SECT
       BIT  7,(IY+1)
       RET  Z ; I'm only
prepared to do a 24 line
COPY during runtime
       LD   A,#7F
       IN   A,(#FE)
       AND  3
       RET  NZ ; SS/Space
keys not depressed ie COPY
not wanted so shoot back
; 24 line COPY comin' up
       LD   B,192
       LD   HL,#4000
       PUSH BC
       LD   A,B
       CP   3
       SBC  A,A
       AND  2
       OUT  (#FB),A
       LD   D,A
       JR   C,COP_L2
; Wait until k'bd is free
  else I'll BREAK out of
; BASIC first chance
       POP  HL
END_2  LD   A,4
       OUT  (#FB),A
       RET  ; Had enough?
COP_L2 IN   A,(#FB)
       ADD  A,A
       JP   M,END_1
       JR   NC,COP_L1
       CALL #0F12
       POP  BC
       POP  HL
       INC  H
       LD   A,H
       AND  7
       JR   NZ,COPY_2
       LD   A,L
       ADD  A,#20
       LD   L,A
       SBC  A,A
       AND  #F8
       ADD  A,H
       LD   H,A
       JR   END_2
; Wait until there are no
grubby hands on MY k'bd
WAIT   IN   A,(#FE)
       AND  #1F
       JR   NZ,WAIT
 Back to the MANAGER -
 I'm worn out!
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