YOUR COMPUTER, December 1983
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AUTO LINE NUMBER for Sinclair Spectrum
by D North
from Your Computer, December 1983


These programs produce automatic line numbering for either the 48K or
16K Spectrum. The machine code program is stored above RAMtop and is
called automatically by diverting the interrupt which occurs every
20ms. The following system variables are used in the program:
	ECHO_E, LAST_K, FLAGS, E_PPC and KSTATE

A checksum is used in each program to warn if there is an error in the
DATA lines. If the "ERROR IN DATA" message appears when the program is
run then carefully check through these lines, correcting any errors,
and run the program again, until the instructions appear.

To turn the program on:
	RANDOMIZE USR 65121
or 32340 for 16K machines. Pressing Enter again should produce 0010
for the first line number. If at any stage you wish to alter the next
line number then delete the number printed and type in the next number
required after which automatic numbering will continue from this line.
The step between line numbers can be altered by POKEing the required
value into 65192 - 32411 for 16K.

If the Enter key is held down the routine will rapidly run through the
line numbers. This can be used if you want to delete part of a
program, by entering the first line number to be deleted and simply
holding Enter down until the last number to be deleted is reached.

If the line number exceeds 9999 a colon - : - will be printed in the
first digit position to warn that the line cannot be entered.

To turn off the routine, delete the last number printed and type:
	RANDOMIZE USR 65111
or 32330 for 16K. This should always be done before using any other
program which uses interrupts.

When the program has been successfully run it can be SAVEd by:
	SAVE "AUTO LINE 48K" CODE 65111,157
or
	SAVE "AUTO LINE 16K" CODE 32330,157
This can then be quickly loaded when required, but remember to set
RAMtop first to protect the program. Alternatively, the program can be
loaded from the BASIC listing, and after turning on the routine the
BASIC lines can be quickly removed by the method described.
Incidentally, it is possible to have program names longer than ten
characters by using keywords in the name. These are only available in
the extended mode.


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BRIDGE BUILDER for Sinclair Spectrum
by Simon Powell
from Your Computer December 1983


Dropping steel sections by helicopter may not be the usual way of
constructing a bridge, but it is the method used in this game.

Type in Listing 1 - the graphics loader - and RUN it. This sets up the
user-defined graphics. Type NEW and then type in Listing 2 - the main
program. Save this on tape by GO TO 9998 - it is saved in two parts,
program and bytes. You can now RUN the program.

It will start by showing a list of the highest scores and, after a
while, will give a demonstration. To start a game, press Space.

The game begins by showing an unfinished bridge with a man on it and a
helicopter flying above. Unfortunately, the man is blind, and he walks
slowly forward while the bridge is built. Use the Space key to drop a
section of bridge from the helicopter. You must drop it next to the
end of the left-hand section of the bridge, to make it longer. If you
miss, then the blind man will walk off the edge and fall in the river.

Fortunately, there are three lifebelts with which to save him, but the
fourth time he falls in he drowns. When you have completed a bridge,
you get a 50-point bonus and another bridge to build. If you get one
of the ten best scores, you can enter your name. Use the right and
left arrow keys to select the correct letter, then press 0. Press
Enter when you have entered your name.


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SOUND SCANNER (aka. Earhole)
-------------
Trevor Cook, Goole, North Humberside.

AS SPECTRUM OWNERS will be aware from their manuals, the EAR socket of the
computer is read via bit 6 of I/OO port 254 decimal. The program contains a
short machine-code routine which returns in the BC register pair, a value
which is proportional to the frequency of any tone which may be present at
the EAR socket. The routine is designed so that if no tone is present, a
value of zero will he returned. I have located the routine at 32600 dec; ie.
the start of the user-definable graphics area on the 16K Spectrum. Owners of
48K machines will need to modify this accordingly by modifying line 400.

Now that we have the means to obtain a tone value, what can we do with it?
There are many possibilities but, to explore just one, the program Soundscan
allows us to graphically represent tones applied to the EAR socket, and
although written in BASIC it is still fast enough to he acceptable.

Type in and save the program with:
	SAVE "SOUNDSCAN" LINE 100
On running, three modes of display will be available. These follow the form
of normal graph, histogram-type graph, and a point-plot display. Options
exist within the program to freeze and restart the display, and to change
display mode.

Lines 250-275 contain the main routine, with the LET L=USR Tone in line 235
collecting the tone value from the machine-code routine. Lines 400-410 POKE
the machine code into memory. Users of 48K machines should change line 405 to
LET Tone=USR "a" if they wish to assign the machine code to the UDG area of
memory. This has the advantage that a change of RAMTOP is not necessary.

Ideally, a cassette recorder with some form of monitoring facility should be
used as it enables the user to listen to the cassette output and observe the
display simultaneously, which reinforces the effects of the program. The
display is particularly impressive if used in Mode 1; ie. normal graph mode
using a music cassette containing a prominent female vocalist as the sound
source.


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HUNCHY - Paul Hargreaves (Your Computer-December 83-Page 132)

PAUL HARGREAVES SAVES EZMERALDA WITH THE HELP OF HIS TRUSTY SPECTRUM.

The program is in two parts so that it can fit in 16K. The first one is for
graphics and the second is the game. The graphics program should be Saved
first before typing in the game.
 Once the game is running the object is as follows:
 To reach Ezmeralda you have to go through five screens. To clear a screen
you must reach the bell rope at the far side of the screen. Beware of the
sniper scaling the wall. If you take too long he will reach the top and after
a while, shoot you with an arrow.
 By the way, he gets faster each round, up until the fourth one. If you manage
to save Ezmeralda without losing a life then a super bonus is awarded.

TYPE: Arcade (Hunchback)


This info file was typed by Michael Bruhn


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WALLS (Bricks) for Sinclair Spectrum
by Graham Pearce
from Your Computer December 1983

[This program needs Issue 2 emulation, because of its use of IN. JimG]

This program will just fit into a 16K Spectrum and works on the 48K
Spectrum as well. The object of the game is to knock all of the bricks
out of the wall at the top while trying to protect a row of bricks at
the bottom. A bonus score of 100 is added after each 1,000 scored. The
game is over after all the bottom row of bricks have been knocked out.
If all the top bricks are knocked out they are then replaced, leaving
the bottom row as it is. 10 points are awarded for each brick at the
top but no score is given for a brick on the bottom which is knocked
out.

On running the game there will be a long pause while the machine code
is POKEd and the message
	Please Wait a Moment
will appear, followed by a prompt
	SKILL LEVEL (1-4)
Level 1 is the easiest and Level 4 the hardest. Only integers are
accepted. To move the bat:
1 - slow ball speed left
5 - slow right
1&2 together - fast - two times the ball speed - left
4&5 together - fast right


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