STORM
by C Hornby
from Sinclair User 20 (November 1983)

[The supporting machine code listing was missed out in the August issue.]
[The complete listing was printed in the November issue.                ]

[I've double-checked the code, but the program doesn't work as listed  ]
[in the mag. Moving left causes the player's "V" character to disappear]
[from the screen, after which all that can be done is to sit and watch ]
[the black squares zipping up the screen.                          JimG]

Part of the Storm program appeared in our August edition, without the
all-important machine code. Here it is again, this time printed in full.
You are situated at the top of the screen. Avoid the storm of black
squares rushing towards you by moving left with "1" and right with "0".
At the start of the game, entering "5" for both level and difficulty
will produce a reasonably fast game. [In fact, that setting is
impossibly fast; 50 is more reasonable (if the program worked). JimG]

C Hornby of Hassocks, Sussex speeded the game by writing part of it in
machine code. [The m/code loader printed in this issue was different
from the original one, but the description for using it still related to
the original one, so I haven't included it here.]


[The ZX81 game 'Storm' seems to have been an unlucky one. First the machine
[code was left out of SU August 1983 and then a bug appeared in the machine
[code in SU November 1983.

[I've disassembled the game and located the single byte that was wrong (it
[was off by a value of 1!). POKE 16613,43 is all that was need to fix the
[game. I've attached the commented disassembly since it might be of interest
[to people to understand how the game works. It was only be disassembling the
[game that I realised that the difficulty level refers to the number of black
[squares that are inserted on each row. It might be worth mentioning this as
[an observation in the instructions. It might also be worth mentioning that
[both the speed and difficulty levels should be between 0 and 255, with 0
[actually equating to 256.

[I've amended the non-working version you have in the archive so that it
[exactly matches the listing in the magazine (you had added REMs and a
[routine to display the machine code bytes). There was also an error in the
[BASIC listing. Line 125 should have been line 135. This didn't actually
[affect the game in anyway but just didn't match the original  listing.

[For any purists out there, I've also created a version of the listing that
[matches what was published in the August 1983 edition.               PaulF]



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