Sigma AMSTRAD User manual

THE
AMSTRAD NOTEPAD! ^
ADVANCED ■ s=7
USER GUIDE ■

THE AMSTRAD
NOTEPAD
ADVANCED USER GUIDE
ROBIN NIXON
Programs written and documented by
Chris Nixon
SIGMA PRESS - Wilmslow, United Kingdom
Thi s One
5ZSR-LLP-2C3T

Copyright ©, R. Nixon and C. Nixon, 1993
All Rights Reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise, without prior written permission.
First published in 1993 by
Sigma Press, 1 South Oak Lane, Wilmslow, Cheshire SK9 6AR, England.
British Library Cataloguing in Publication Data
A CIP catalogue record for this book is available from the British Library.
ISBN: 1-85058-515-6
Typesetting and design by
Sigma Press, Wilmslow
Printed in Malta by
Interprint Ltd.
Distributed by
John Wiley & Sons Ltd., Baffins Lane, Chichester, West Sussex, England.
Acknowledgement of copyright names
Within this book, various proprietary trade names and names protected by copyright
are mentioned for descriptive purposes. Full acknowledgment is hereby made of all
such protection.

PREFACE
At first sight it might seem a step backwards and a rather surprising move for
Amstrad to release a 64K Z80-based 'laptop'-type computer when the market
definitely looks like PC-compatible is the way to go, and laptops being the fastest
growth area.
But maybe that's the point. There is a large group of people who know that all they
need is a cheap, easy-to-use and (as the Notepads proudly proclaim) user-friendly
interface - without having to learn about using DOS or Windows.
Amstrad are renowned for using tried and tested formulae, which the Z80 certainly is
- just look at how well they did with the PCW family. What's more, Z80s are cheap,
as are the additional chip sets that go with them and, because of their low power
consumption, you get up to 40 hours use out of an NC100 - about 10 times more than
with most PC-compatible laptops.
And Amstrad made a very sensible decision in their choice of software. By porting
Protext across to it they have a top-selling word-processor also available on a number
of platforms, including the Amstrad CPC and PCW, Archimedes, Atari ST, Amiga
and PC compatibles. In one go, Amstrad have a product that can be file compatible
with just about every other popular computer.
By removing Protext's command mode (well, not entirely, as you'll see later), they
came up with a very simple system of colour-coded key combinations so that, no
matter where you are in the Notepad, you can move to any other in-built application
at a key press. But, in my opinion, one of the best things to be incorporated was the
BBC Basic ROM which allows you to adapt the computer fully to your own
requirements.
And that is what this book concentrates on. In it you will discover how you can use
BBC Basic to write applications to complement seamlessly the in-built applications,
with the user never even knowing they are in Basic.
Even if you're not a programmer, the explanations of how the Notepad works should
interest you, but if not a large proportion of this book is taken up with ready-made

iv
The Amstrad Notepad
programs ready for you to type in and run. So, without needing to know a thing about
programming, you can add a writing style checker to your Notepad, or there's a full
scientific calculator, a food additive database, a graphical world time zone viewer, a
mortgage calculator and a whole lot more.
For the more technically minded, full details on the Notepad's firmware calls,
input/output ports and system variables are provided, including how you can make
use of them yourself. You'll even learn how to create enure system applications to
run from a RAM card. Everything you need to know in order to do this is in this
book, even down to a fully working Z80 disassembler you can type in and use
immediately.
In fact this book is packed with undocumented information about the Notepad (and
even the Z80 microprocessor itself) that you are unlikely to find anywhere else.
Along with the comprehensive index, you will find it to be a complete, one-stop
reference to using and writing Notepad programs, as well as a valuable source of
additional software for your Notepad.
Thanks are due to Mark Tilley and Gavin Every at Arnor Ltd (the programming
team) as well as to Cliff Lawson the Notepad Project Manager at Amstrad Pic for
much of the technical information that appears here. Because these details came
directly from the programmers you can be sure that they are as accurate as possible.
Thanks also to John Blackburn for his invaluable assistance in the preparation of this
book, and to Richard Russell, the author of the Notepad BBC Basic interpreter, for
his assistance with the final manuscript.
Robin Nixon
To Julie and Naomi

Contents
SECTION 1 - THE PROGRAMS 1
THREE GOLDEN RULES 2
GET IT RIGHT 2
AUTO 3
USING THE PROGRAM 3
HOW IT WORKS 4
BIOMON.BAS 6
USING THE PROGRAM 6
HOW IT WORKS 7
CALC.BAS 12
USING THE PROGRAM 13
HOW IT WORKS 15
CH ART.B AS 22
USING THE PROGRAM 23
HOW IT WORKS 23
COOKIE.BAS 26
USING THE PROGRAM 26
HOW IT WORKS 27
DEVIL.BAS 33
USING THE PROGRAM 34
HOW IT WORKS 35
FOOD.BAS 47
USING THE PROGRAM 48
HOW IT WORKS 49
INKEY.BAS 56
USING THE PROGRAM 57
HOW IT WORKS 57
MORTGAGE.BAS 58
USING THE PROGRAM 59
HOW IT WORKS 59

vi The Amstrad Notepad
READYREC.BAS 61
USING THE PROGRAM 62
HOW IT WORKS 63
SCALES.BAS 68
USING THE PROGRAM 69
HOW IT WORKS 69
STYLE.BAS 75
USING THE PROGRAM 76
HOW IT WORKS 77
TIMEZONE.BAS 88
USING THE PROGRAM 89
HOW IT WORKS 89
ZAP.BAS 100
USING THE PROGRAM 101
HOW IT WORKS 101
SECTION 2 - REFERENCE 121
1. CONTINUED . . . FROM THE NOTEPAD MANUAL 122
REGISTER VARIABLES 126
2. UNDOCUMENTED FEATURES 129
TRANSFERRING BBC BASIC PROGRAMS 129
QUICK MACRO ASSIGNING 129
LINE DRAWING CHARACTERS 130
PAGE DISPLAY MODE 130
USING THE FILE SELECTOR 131
PEEKING ABOUT 131
UNDOCUMENTED SELF-TEST 133
SAVING THE SCREEN 134
3. WRITING EXTERNAL PROGRAMS 145
USING THE NOTEPAD'S LCD DISPLAY 146
4. THE NOTEPAD'S INPUT/OUTPUT PORTS 151
5. THE JUMPBLOCK ENTRIES 157
KEYBOARD FUNCTIONS 158
SCREEN DISPLAY FUNCTIONS 160
PARALLEL AND SERIAL PORT FUNCTIONS 166
CLOCK FUNCTIONS 169
MEMORY ALLOCATION FUNCTIONS 170
FILE I/O FUNCTIONS 172
MISCELLANEOUS FUNCTIONS 178

Advanced User Guide vii
6. THE SYSTEM VARIABLES 182
BBC BASIC MAIN SYSTEM VARIABLES 185
7. RECOVERING FROM LOCK-OUTS 186
8. THE COMPLETE Z80 INSTRUCTION SET 188
9. THE UNDOCUMENTED Z80 INSTRUCTIONS 219
SECTION 3 - APPENDICES 225
APPENDIX 1: NC100 JUMPBLOCK ENTRY POINTS 226
APPENDIX 2: INPUT/OUTPUT PORTS (&0000 - &00FF) 229
APPENDIX 3: KEYBOARD SCAN CODES 230
APPENDIX 4: THE COMPLETE SET OF Z80 INSTRUCTION CODES. . . 232
APPENDIX 5: NEW NOTEPAD MODELS 247
APPENDIX 6: EXTRAS 248
GET CONNECTED WITH LAPCAT 248
EXPAND YOUR NOTEPAD WITH A RAM CARD 248
ORDER THE DISK OF THE BOOK 248
ORDER FORM 249

SECTION 1
THE PROGRAMS
Whether or not you are a programmer, this collection of programs has been designed
to accompany the applications provided with your Notepad. They have been written
in such a way that no knowledge of programming is required to use them and you can
call them up by simply pressing [Function] [B], so you don't even need to know any
Basic commands. Just type in the programs, check them and save them.
On the other hand, detailed descriptions accompany every program in this section,
including line by line running commentaries, descriptions of the functions and
procedures used, and an explanation of all the main arrays and variables.
Using all this information in conjunction with the listings you will be able to pick up
on the various methods used and then incorporate any ideas you like into your own
programs. To this end the variety of programs has been kept as wide as possible and
a broad range of programming styles and techniques have been used, covering areas
such as using the built-in assembler, handling strings, variables and arrays, processing
and storing data, directly accessing the display RAM, the non-standard Notepad VDU
codes and much more.
All the programs are written in BBC Basic and some contain sections of assembly
language to achieve effects that, if written in Basic, wouldn't be possible, would take
too much space to write, or would run unacceptably slowly.
The programs are self-contained, and range from a useful scientific calculator to a
world clock featuring a map of the earth. There's also a version of the classic game
Towers of Hanoi to while away the odd hour, and if you are fond of writing you

2
The Amstrad Notepad
might like to pass your efforts through the compact style checker and see how they
measure up.
Programmers may be particularly interested in the assembly language routine that
performs an instant scan of the keyboard, in a similar fashion to BBC Basic's
negative INKEY(-n), (as opposed to Basic's INKEY or INKEY$, which can only
return keys at the speed of the current keyboard repeat rate). There's a full chart of
the Notepad's character set - useful for designing screen layouts or games, and a
complete Z80 disassembler so you can delve into the inner workings of other
programs.
THREE GOLDEN RULES
There are three Golden Rules you must bear in mind when typing in program listings,
and which you should always follow in order to prevent typing mistakes - or even
crashing or erasing programs.
Golden Rule number one:
Make sure you save your work before you try it out. It's very tempting to type RUN
every so often to see the effect so far, but even if you save the program first you are
strongly advised against it - especially where there is machine code involved, as you
could lock-up your Notepad.
Golden Rule number two:
Read the listing carefully. A common error is to confuse any of the following for
each other: Lower case "1" (lower L), "i" (lower I) and "1" (one). Another common
mistake is to confuse the capital letter "O" with the number "0".
Golden Rule number three:
Don't delete any REM lines or lines containing just a colon As a matter of style
most of the programs in this book avoid GOTOs in the main code, but all of them
contain at least one ON ERROR GOTO line (and listings from other sources may
make more liberal use of GOTOs). So, if any GOTOs happen to point at a line that
you've deleted as being unnecessary you'll get into all sorts of bother.
GET IT RIGHT
If all else fails (or even if you simply prefer not to type in the programs), you can
order a disk containing all the listings fully tested and ready to run, along with a lead
and software to transfer them to the Notepad, using the form in Appendix 6.
Please also remember that a Notepad without a RAM card may only be able to hold
two to three or so small to medium Basic programs at any one time. If you really
want to make use of your computer and not run into memory storage problems you
should buy a RAM card. One such source is also given in Appendix 6.

Advanced User Guide
3
AUTO
Menu system
fiUTO
BIOMON.BRS
CfiLC.BfiS
:hrrt : "
":i.Rfip
f23l
494 C
2980 C
5=02=1
93-02-1
93-02-1
2995 C 93-C2-1
_ 28
4235
3-02-1
3-02-1
14:28
14:23
14:29
14:29
15:11
_ 10DE2.RR
COOKIE. BAS
DEVIL. BfiS
EXTERNAL , RfiP
FILESEL.RfiP
FILTRRNS.RfiP
FOOD . BfiS
ocuments ♦
5536 C 93-02-11 14:29
" 93-02-11 14:30
93-02-11 15:15
93-02-11 15:19
■* 02-11 14:53
02-11 14:30
AUTO, the menu system for Basic programs
This is the first and most important of the programs because it provides an
easy-to-use interface for running the other programs, without needing to enter BBC
Basic's command mode.
It works by taking advantage of a feature built into Notepad Basic which checks for a
file called AUTO whenever you enter Basic (normally by pressing [Function] [B]). If
such a file exists Basic proceeds to load and run it, rather than just dropping into
command mode.
USING THE PROGRAM
Type in the listing and save it as AUTO before trying it out. Note that you must NOT
call it AUTO.BAS (although all the other programs should use the .BAS extension),
or the file will not be recognised by Basic's initialisation routines. It is also essential
that you save the program before running it in case you have made any typing
mistakes and something goes wrong or, perhaps, you did type it in correctly but
accidentally loaded in another program while testing it.
Once saved type:
RUN
and press [Return]. You should then see the Notepad's standard file selector which
you can now use to call up a program in the same way you might select a file for
editing in the word processor.
Because this program prevents access to Basic's command mode you might wonder
how you are now going to be able to type in more programs. The answer's simple:
you can exit from AUTO at any time by pressing [Stop]. You are then dropped into
command mode and, if you want to enter a new program, type:
NEW

4
The Amstrad Notepad
and off you go. Or, if you accidentally exited from AUTO you can get back in by
pressing [Function] [B].
HOW IT WORKS
The program is described as follows, with line numbers on the left and explanations
on the right.
30-40 Clear memory and dimension A% so that it's just big enough to
hold the machine code which will be assembled.
50-60 Assemble the code and call it.
70 If the first character of the file name is 0 then there is no file
name so print a message and exit.
80-1 10 Copy the file name returned by the machine code routine into the
variable R$.
120 Check whether the file name has an extension of .BAS. If not, it
is not a Basic program (at least, not as far as the program is
concerned, because the .BAS extension is the recommended
method of declaring whether a file is a Basic program). So, if
not, refuse to attempt to run it and call the file selector again.
130 Load the selected program into memory (replacing AUTO) and
run it.
160-190 Prepare for a two-pass assembly using a FOR.. .NEXT loop and
set the program point (P%) to the machine code destination
address at the start of each pass.
200 Call the Notepad's built-in File selector.
210 Set the register DE to point to the start of where the File selector
will have stored a file name if one was selected.
220-250 If the Carry flag is set then no file was selected because the user
pressed [Stop], so set the first byte of the file name which is to
be passed back to Basic (pointed to by DE) to a zero to indicate
this, and then return.
270-340 A file name was selected so copy all the characters in the name
to a known location in memory starting at 'buffer' and then
return.
Functions and procedures
PROCselect Assembles the machine code required to call the File selector
and then return the name of any selected file to a known area of
memory that can be accessed from Basic.
Main variables and arrays
A% 22 bytes of memory used to hold the assembled machine code.

Advanced User Guide
5
buffer The start of 13 bytes of memory within A% which are used to
hold any file names.
R$ Holds a copy of a selected file name ready to CHAIN it in.
J% Temporary loop counter used to control the copying of a file
name from memory into the string RS.
P% The pointer to where machine code is to be assembled by the
assembler.
found Start of machine routine where a file name has been found.
loop Label marking the start of the machine code loop to copy a file
name to a known location, useable from Basic.
The program
10 REM BBC Basic menu system
20 :
30 CLEAR
40 DIM A% 22
50 PROCselect
60 CALL A%
70 IF buffer?0 = 0 THEN CLS: PRINT "Press [Function] [B] for
menu . " : PRINT : END
80 R$=""
90 FOR J%=0 TO 11
100 IF buf fer?J% THEN R$=R$+CHR$ (buf fer?J%) ELSE J%=12
110 NEXT
120 IF RIGHT$(R$,4) <> " .BAS" THEN GOTO 60
130 CHAIN R$
140 :
150 DEF PROCselect
160 FOR PASS=0 TO 2 STEP 2
170 P%=A%
180 [
190 OPT PASS
200 CALL &B8C3
210 LD DE, buffer
220 JR C, found
230 LD A,0
240 LD (DE) , A
250 RET
260 .found
270 LD B,12
280 .loop
290 LD A, (HL)
300 LD (DE) , A
310 INC HL
320 INC DE
330 DJNZ loop
340 RET
350 .buffer
360 ]
370 NEXT
380 ENDPROC

6
The Amstrad Notepad
BIOMON.BAS
Biorhythm Monitor
Biorhythm Monitor
Enter your Date of Birth
Day (1-31) ; |
4* I
FT
Si
...Uid..'
BIOMON.BAS, showing physical, intellectual and emotional strength
The study of biorhythms is based on the ancient belief that our physical, intellectual
and emotional states run in fixed, regular cycles from the day that we are born.
Whether you believe this or not, it means that we can calculate these states for any
day of a person's life, given just their date of birth and today's date. And as the
cycles are regular, they lend themselves to rather attractive looking sine wave charts,
which used to be hand-drawn by astrologists in the days before computers.
However, this is extremely time consuming, and as the formulae for calculating the
number of days that lie between a person's birthday and any other date are complex,
they make an ideal subject for a computer program to handle. In fact, there probably
isn't a computer in existence that hasn't had a biorhythm calculator written for it (as a
demonstration of the machine's graphics capabilities as much as for any other
reason).
The program BIOMON.BAS uses the standard biorhythm cycles to plot a personal
chart for a 35-day period with today's date in the middle. It differs slightly from other
programs of this type by telling the user in plain English what each line on the chart
represents, and whether today's level is good or bad for that particular chart line.
USING THE PROGRAM
Type in the listing and save it as BIOMON.BAS before trying it out. This is essential
in case you have made any typing mistakes and something goes wrong.
Now type:
RUN
and press [Return] and you will be prompted to enter your date of birth. Type in the
day of the month on which you were born, and press [Return]. Then type in the
number of the month, press [Return], and then enter the year - you can enter this
either in full, as in 1964, or in shorthand, as in 64. Don't forget to press [Return] after

Advanced User Guide
7
entering the year. If you make a mistake at any one of these three stages, Biomon will
repeat that stage until it's happy with the result.
Biomon now makes a final, more involved check to see if the date you have just
entered actually existed. It does this by checking that the month you have entered has
at least the number of days you have given as the day of the month on which you
were born, and leap years are taken into account at this stage. If Biomon finds an
error it will report Bad date - press SPACE, and you will have to re-enter the whole
date.
If all is well with the date, the screen will clear and the plotting will begin. Each line
is drawn with a different dot pattern, making it easier to tell them apart.
When the plot is finished (it takes about half a minute), the box on the chart
representing today's date will be highlighted in inverse, and the window on the left
will show a key for each of the three chart lines together with a one-word summary
of how good or bad each one is today.
If you can't wait for the full plot you can cut it short by pressing [Q], which jumps
straight to the summary screen - useful if you're not interested in seeing the general
pattern of cycles.
HOW IT WORKS
40
Points the Basic error handler to Biomon's own error handling
routine at line 940.
Calls PROCsetup to initialise everything.
Calls PROCinput to get a birth date, followed by PROCdays to
count the number of days that have elapsed. Then calls
PROCgraph to plot the chart, and finally PROCreport to
summarise the current state of each chart line.
50
60
90-130
Initialise the main graphics constants. Altering these values will
have a major effect on the resulting chart.
Dimension all arrays and read in all the data.
Draws a box enclosing the entire screen area.
Draws a vertical line to separate the graph area from the
information window.
Prints the program title.
Calls the date prompt window into operation and returns from
the procedure.
Flushes the keyboard buffer by calling INKEY$(0) until no keys
are returned.
Prompts for the date of birth to be entered.
140-180
190
200
210
220
250
260

8
The Amstrad Notepad
270
280
290
300-320
330
340
410
420
430
440^50
460
470-520
560
590-600
610
620-630
640
650
660
690
700
Repeatedly prompts for the day of the month until the input is
within legal limits.
Repeatedly prompts for the month unul the input is within legal
limits.
Repeatedly prompts for the year until the input is within legal
limits.
Check to see if the date specified exists.
Informs the user if the date doesn't exist and waits for the
message to be acknowledged.
Repeats the entire input process if the date entered doesn't exist.
Extracts the current day of the month and the current year from
the system clock.
Extracts the name of the month from the system clock and
converts it into a number between 1 and 12, by comparing it
against each entry in the array m$().
Multiplies the elapsed years by 365 to get the rough number of
days involved.
Adjust the days according to the birth month and current month.
Adjusts the days further according to the day of the month of
birth and the current day of the month.
Adjust the days further according to the number of leap days
involved.
Calculates whether y% is a leap year or not.
Clear the information box and print the current date, together
with the birthdate being plotted, in preparation for the plot.
Sets up a graphics window and origin, and clears the new
graphics window.
Draw the chart axis, and dotted boxes to delimit each of the 35
days to be charted.
Sets the start day to be 17 days ago and starts the main
FOR.. .NEXT loop for the X coordinate, checking for the [Q] key
at the start of each loop.
If [Q] wasn't pressed, calls PROCbio() inside a further
FOR.. .NEXT loop to plot the current Y position of each line.
Ends the main plot loop, inverts today's box on the chart and
exits the procedure.
Fetches the cycle length for the current line and whether it is in
its dot or dash phase.
Plots a new point for the current line if it is inside its dot phase.

Advanced User Guide
9
710 Checks to see if current line's dot or dash phase has reversed. If
so, flips the line's dot phase flag.
720 Stores the new dot phase flag setting for the current line.
760-830 Draw a short sample of each line's dot pattern to be used as a
key, during which time a score for each is calculated in line 810,
representing an entry in the array of comments well$(). Display
the report header when the loop is complete.
840-860 Print the name of each cycle, together with a single-word
comment from the list held in well$0, pointed to by the relevant
entry in the score table well%() (which was calculated back in
line 810).
870 Waits until [Space] is pressed before returning from the
procedure.
890 Holds the data for the number of days in each month.
900 Holds the names of each month, as used in line 420 to calculate
the number of the current month.
910 Holds the cycle length in days for each of the three chart lines,
followed by the length of the dot and dash for that line, followed
by the initial dot-dash phase to start with.
920 Holds the single-word comments which are used at the end of
each plot to summarise the state of each chart line.
940 Points the Basic error handler to a full error report in the event
of a further error occurring while attempting to run the menu
program AUTO. This is in case AUTO isn't present on your
Notepad.
950 Attempts to run the menu program AUTO if the error was
generated by pressing the [STOP] key.
960 If the error was caused by something else, or if AUTO isn't on
your Notepad, a full error report is displayed.
970 After the error report the Notepad will be left in BBC Basic, so
this message is displayed to remind users of how to return to the
Notepad main menu.
Functions and procedures
PROCsetup Dimensions arrays and reads in all data, initialises main variables
and draws a box.
PROCinput Prompts for the day, month and year of birth.
PROCwinl Sets up a text window for the birthdate prompt.
PROCwin2 Sets up a date window for the birthdate input.
PROCdays Calculates number of days elapsed since birth.

10
The Amstrad Notepad
PROCgraph Plots a biorhythm chart for the birthdate just entered.
PROCbio Plots a dot at the current X coordinate for any of the three lines.
Called by PROCgraph.
PROCreport Displays a key for the graph and a single-word summary for
each line.
FNleap Returns TRUE or FALSE according to whether the passed
variable is a leap year.
Main variables and arrays
m%() Number of days in each month.
m$() Abbreviation of month names.
period%() Length of each cycle in days.
gap%() Length of each line's dot and dash in pixels.
flag%() Keeps count of each line's current dot or dash phase.
well%() Numbers representing how good or bad each cycle is today.
well$() Store of single-word summaries.
yc% Y centre of graphic window.
xc% X centre of graphic window.
px% Number of pixels per day horizontally.
xm% Width of graphic window.
ym% Height of graphic window.
d% Number of days since birth, as returned by PROCdays.
sd% Number of days since birth up to 15 days ago (the start of the
plot).
dl% Day of birth.
ml% Month of birth.
yl% Year of birth.
d2% Today's day of the month.
m2% Today's month.
m3% Today's year.
t% Number of current line being processed (1, 2 or 3).
quit% Whether Q was pressed during plot.
The program
10 REM Biorhythms
20 :
30 CLS
40 ON ERROR GOTO 940
50 PROC setup