sz81 Code

* -*- outline -*-

	    Mine81 - public domain by Russell Marks, 1997

		  A minesweeper clone for the ZX81.


* License

Mine81 is public domain, you can do what you want with it. I would
appreciate it if you could copy this text file whenever you copy the
game, though.


* Playing Mine81

Mine81 is much the same as any other minesweeper game, right down to
the smiley face at the top of the screen. :-) But here's a brief
description all the same:

You have to mark off all the mines (and not tread on any!), given only
the number of mines next to each square you tread on - there can be up
to 8. This is displayed on each square you step on as a digit, except
for those squares with zero mines around them which simply appear
blank. If you tread on a `blank' square like this, all similarly blank
squares connected to it are shown - and the same for *those* blank
squares, etc. - so finding blank squares is a Good Thing, as it can
reveal large parts of the minefield.

There isn't as much luck involved in the game as there may initially
seem to be. If you get a reasonable start, you can often deduce where
each mine is with luck taking no further role in the game at all. As
ever, practice is the key; if you've not played a minesweeper game
before you may want to play the "very easy" game quite a bit before
attempting the higher levels.

Minesweeper games traditionally use mouse control. Since this is
clearly not practical on a ZX81, Mine81 lets you control a cursor
which - other than being moved with keys - acts in the same way.

You move left/down/up/right with H/J/K/L (vi keys), or S/X/E/D
(old-style wordstar-ish keys). You tread on a square with either V or
Space, mark a square you believe to be mined with 1 or M, and you can
unmark a square you think you marked wrongly with 3 or U.


* Known bugs

It takes ages to show the blank bits. My code probably isn't hugely
efficient, and hey, it *is* only a ZX81! :-) Besides, the timer is
deliberately stopped during the blank-finding bit to avoid any
unfairness.

There's no high-score table, so if you want to beat your own best time
you have to check this by hand.


* Assembling

You don't have to assemble Mine81, it comes as a .P file along with
the source. But, since I'm distributing the source, it makes sense to
describe how to assemble it.

You'll need a Unix box, and `zmac' (look on sunsite.unc.edu in
/pub/Linux/devel/lang/assemblers). Compile and install zmac, then do
`make' and it should build mine81.p.


* Contacting me

You can email me at russell.marks@ntlworld.com.


Share and enjoy! 

-Rus.