
FRONT COVER 




INTRODUCTION 




PUBLISHING INFORMATION 




PREFACE 




CONTENTS 




ACKNOWLEDGEMENT 




EXTENDING YOUR ZX81 





The 16K RAM pack 




New programming considerations 




The ZX printer 




How to use this book 



AN EXTRA 16K 





Memory map and system variables 





Manipulating memory locations 





More memory locations 





A memory test program 




PROGRAMMING UTILITIES 





Utility One  Memory use 




Utility Two  Variable use 




Utility Three  Renumber 



16K GRAPHICS 





Full graphics  Depth charge game 




Squash 




Screen layout 




Screen PEEKing and POKEing 




Maze game 




Scrolling graphics 




Ski run game 




Paged graphics 




Conclusion 



DESIGNING LARGE PROGRAMS 





Designing a program 




Using subroutines 




An extended RETURN 




Collections of programs  Menus 




Userfriendly programs 




Debugging 



TAPE STORAGE OF DATA 





The tape system 




Data storage 




Statistics program 



NUMBER FORMATING 





Truncating and rounding 




Aligning decimal points 




PRINT USING 




Interest calculator 



THE PRINTER 





How the printer works 




Low resolution printing 




High resolution plotting 




Plotting a sine curve 




A lower case or special character set 




Conclusion 



ADVANCED RANDOMNESS 





Continuous events 




The Normal Distribution 




The CHI Squared Distribution 




The Exponential Distribution 




The Binomial Distribution 




The Poisson Distribution 




Monte Carlo integration  finding PI 




Problems with random numbers 




A business simulation 




Sinclair's Triangle 




Conclusion 



MACHINE CODE PROGRAMMING 





Why is BASIC so slow? 




The characteristics of machine code 




The ZX80 




The instructions LD and ADD 




A short example program 




A second example  reversing the screen 




Next steps 



ALSO RECOMMENDED 




TAPES 




NOTE 




BACK COVER 


