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Now That You Know Apple Assembly Language,
What Can You Do With It?..................Review by Bill Morgan

Do you know the difference between LDA LABEL,X and LDA (LABEL),Y but wonder when to use which?  Are you confused by the way PHA, PHA, RTS doesn't go home, but jumps somewhere else entirely?  Do you know what the 6502 opcodes do, but still feel lost when it comes time to combine them into a program?

Jules Gilder, a long-time contributor to several of the Apple Magazines, has written a book just for you.  He spends about 190 pages covering the intermediate level of assembly language programming in the Apple II computer.  His programs are very well commented, and the accompanying text contains almost a line-by-line discussion of how and why each program works.

Gilder concentrates on the Apple-specific features of 6502 programming:  input and output hooks, the internal speaker, and basic linkage to Applesoft.  This combination should make this book especially appealing to those of you who have learned 6502 from a "generic" book and want to find out how to apply your new knowledge to your Apple II's.

Here is a summary of each chapter of Now That You Know...:

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1) Before You Get Started -- This is an introduction to assemblers and their conventions.

2) Getting Information out of Your Computer -- This chapter covers simple output, including message printing and decimal number display.

3) Getting Information into Your Computer -- Here we get into reading keystrokes and lines, handling decimal input, and also menu control structures.

4) Stealing Control of the Output -- This one goes into taking over the output hook to do custom printer setup codes and drivers, output filtering, and formatting.

5) Stealing Control of the Input -- Learn how to grab the input hook to add a custom cursor, numeric keypad, an in-memory EXEC simulator, an Applesoft keyboard macro facility, and a lower-case input driver using the shift-key modification.

6) Using Sound in Your Programs -- How to use the Apple's built-in speaker to create a variety of sounds.

7) Learning to Use the Ampersand -- Here are techniques for hooking into the &-vector to do hexadecimal input and output in Applesoft, find a program line in memory, append two Applesoft programs, and revive a program lost by the NEW command.

8) Expanding Applesoft BASIC -- Now we can have computed GOTO, GOSUB and LIST, do double-byte PEEKs and POKEs, switch between two Applesoft programs sharing memory and variables, and add function keys to control output modes.
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The only real weakness in this book is the complete lack of attention to the Apple's graphic display possibilities, and comparatively little coverage of dealing with DOS (and only one small appendix covering conversion to ProDOS.)  I suppose Gilder regards these as more advanced topics.  Hopefully he will see fit to focus on such subjects in a future book.

Gilder's company, Redlig Sytems, Inc., also has diskettes of all the programs in the book, in either source or object form.

We'll be carrying Now That You Know... for only $18 + shipping.





Apple Software Protection Digest

Gilder is also starting a newsletter on the subject of Apple software protection.  This publication is devoted both to protecting your own programs and defeating the protection on others'.  Here is part of Jules' description:

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Apple computer owners need a place where they can get more information about software protection.  They need a forum where they can exchange ideas with others who face the same or similar problems.  They need to know what software protection is, how it's implemented, what are the consequences of it, how it can be overcome if necessary and if there are any comparable unprotected alternatives to particular protected software packages.

Apple Software Protection Digest will provide you with this information and more.  It will show you new ways to protect, unprotect and backup your programs.  It will teach you how to prevent others from accessing your programs and it will show you how to make them more difficult to copy.  In addition, you'll learn how to overcome these and other protection schemes that are in use.  You'll learn how to use the powerful, but compli- cated nibble copy programs.  You'll also learn how to crack or remove protection entirely from many programs.
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In the first issue he covers hiding Applesoft program lines (and finding them once they're hidden), making a machine language program automatically execute when BLOADed, protecting a disk by adding extra tracks and leaving some tracks unformatted, backing up The Print Shop, and he reviews the Copy II Plus nibble copier.

As a special offer for AAL subscribers, Gilder will give you a free copy of the first issue of Apple Software Protection Digest.  Just send your name and address to Redlig Systems, Inc., 2068) 79th St., Brooklyn, NY, 11214.  Be sure to mention that you are an AAL reader.  The subscription rate is $24 for one year, or $42 for two years.
