Category : Assembly Language Source Code
Archive   : D86V372.ZIP
Filename : D01.DOC

CHAPTER 1 INTRODUCTION AND LEGAL TERMS


Introduction

D86 is a screen-oriented assembly language debugger for the
IBM-PC, compatibles, and most not-so-compatibles (Wang-PC, TI-PC,
Tandy 2000, Sanyo 55x, Zenith Z-100, and DEC Rainbow). D86 is
the finest debugger available, at any price under any conditions,
for the following:

1. Learning 8086 assembly language.

2. Exploring the machine state of your computer (memory
structure, registers, etc.)

3. Doing assembly language program development using my A86
assembler.

4. Doing any kind of debugging involving the floating point (8087
or 287) coprocessor.

In contrast to software firms who attempt to restrict the
distribution of their software through protection schemes, I
encourage free distribution, and trust that those who use my
products will pay for them. Please keep in mind the fundamental
good spirit of free-distribution software as you endure the
following barrage of legalities. Then evaluate the outstanding
value that the D86 package offers you. I assure you that you
will not be disappointed.


Legal Terms and Conditions

This package is provided to you under the following conditions:

1. You may copy this entire package, and give it to anyone who
accepts these terms. The copies you distribute must be
complete and unmodified. You do not have to be registered to
distribute this package.

2. Even if you have not yet obtained full execution rights, you
may execute the programs in this package, in order to evaluate
them. If you decide that D86 is of use to you, you must
become a registered user by sending $50 US ($52 overseas) to:

Eric Isaacson
416 E. University Ave.
Bloomington, IN 47401-4739

For your convenience, I now accept Visa, MasterCard and
American Express, by telephone or mail. My number is
(812)339-1811.
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For the convenience of users in Great Britain, I have
authorized the firm Shareware Marketing to collect
registrations for me. We'll try to keep the prices about the
same whether you register through me or through them; it's
your choice. Their address is 3a Queen St., Seaton, England
EX12 2NY; telephone 0297 24088. They'll send me a list of
registered users at the end of every month, and I'll send an
acknowledgement to each user when I get the list. So if you
haven't heard from me by the end of the month following your
registration with them, please let me know.

Your registration includes the latest diskette (3.5 or 5.25
inch, double density), that also includes the INSTALLD and
MAPD86 tools available to registered users only. You may
order further updates for $10 US, or $12 US if you are
overseas. Once you register for this package, you are
registered for all future versions -- you have permanent
rights to execute D86 on one computer. As long as I'm in
business, you can get the latest version for just the update
fee.

To use D86, you must have the associated assembler, A86. A
copy of A86 (without all of its documentation) is included in
the D86 package. If you are using D86 to debug only programs
written in languages other than A86, then you do not need to
register for A86. If you are programming in A86, then you
must register for A86. There is a discount for combined
registration of A86 and D86. Instead of $50+$50 = $100, the
charge for both packages is $80 ($82 overseas), without the
printed manual.

I also offer a printed version of this manual, covering both
A86 and D86. The manual is printed on sheets 8.5 inches high
and 7 inches wide, with a plastic ring-style binding so the
book can lay flat. If you order with your registration the
manual is an extra $10 to North America, $15 overseas. If
you've already registered and now want the manual, add $10
($12 overseas) for the update disk that the manual is bundled
with. There is a limit of one manual per computer registered
(except you may reorder when there is a substantial revision
to the manual).

Indiana residents need to add sales tax. At the current rate
of 5%, the prices for Indiana residents are $52.50 for one
product, $63 one product with manual, $84 both products,
$94.50 both products with manual, $21 manual if already
registered.

Educational institutions and training facilities MUST be
registered in order to use D86 in courses. Contact me for
special terms.

Companies and government agencies MUST be registered in order
to use D86 for their work. Again, contact me for special
terms.
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3. You may not sell this package to anyone. If you distribute
this package on a diskette, any fees you collect must be
specified as materials/handling, and may not exceed $10 for
the diskette.

4. You are completely responsible for determining the fitness or
usability of this package. I will not be liable for any
damages, of any kind, arising from any failure of any programs
in this package to perform as expected.


Registration Benefits

Thank you for enduring the legalities. They are there to protect
me, and also to convince you that this is my business, from which
I expect to make a living. I'll now return to a softer sell, to
try to make you want to register for my products.

There is a certain amount of ambiguity about when you're still
evaluating D86, and when you're really using D86 and should
register for it. Some cases are clear (e.g., you're a school
using D86 to teach a course); but many are not. In practical
reality, it up to you to decide: you are "on your honor". Also in
practical reality, most users who ought to register haven't, yet.
For most, it's not dishonesty but merely procrastination. So I
have provided some incentives, to prod you into registering.

One incentive is the printed manual, which only registered users
can purchase. I haven't left anything out of the disk version of
the manual, but the printed version is formatted and bound much
more nicely than if you print it yourself.

Another incentive, included if you register both A86 and D86, is
a preliminary test version of A386 and D386. At this writing,
all instructions though the Pentium are implemented, except
32-bit indexing (e.g. [EAX]) and assembly to a 32-bit
protected-mode segment (in which you need override bytes for
16-bit operands instead of 32-bit operands).

Another incentive is a file REG_ONLY.ZIP containing extra tools
that enhance D86's usefulness. If you program in languages other
than A86, and produce the program with a linker, you can use the
tool MAPD86 to convert a link MAP listing into a SYM file
readable by D86, so you can do symbolic debugging. If you have a
386-based machine, you can add the D command to D86, allowing you
to set memory breakpoints.

Finally, there are the intangible incentives. You know you've
done the right thing. You're letting me know that you appreciate
what I've done. You're letting the world know that quality
software can succeed when distributed as shareware.
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Overview of D86

D86 is a screen-oriented program that allows you to troubleshoot
faulty computer programs written for the IBM-PC and all
compatibles, Wang-PC, TI-PC, Tandy 2000, DEC Rainbow, and Sanyo
computer. It "freezes" the state of your program, and allows you
to investigate the values of registers, flags, and memory. You
can monitor your program's execution by stepping it one
instruction or procedure at a time; or you can start your program
running, telling D86 to stop it when it reaches certain
locations. D86 recognizes the symbol-table output of the A86
assembler, creating a symbolic disassembly of your A86 program,
and allowing you to refer to locations and variables by name.

The primary design criterion for D86 is ease of use. This is
reflected in the most notable features of D86:

* You don't need to ask D86 what the values of registers and
flags are. They are there, automatically, at a fixed location
on the screen.

* You don't need to ask D86 where in your program you are
stopped. A disassembly is always generated, at another fixed
location on the screen. The disassembly gives a hefty chunk of
your program, not just the single instruction you are at. A
cursor next to the disassembly marks the current location. The
disassembly chunk remains fixed as you step though it, allowing
you to follow the flow of the program much more easily. If you
wrote the program using A86, the disassembly is symbolic,
giving instruction operands by name, and labelling disassembly
locations when possible.

* You don't need to ask D86 what is on the machine stack. A
display of the top elements of the stack is always generated,
at yet another fixed location on the screen.

* You can set up windows into memory, displaying memory contents
in a variety of types. The types can even be mixed, to display
complicated structures. The windows will stay at the same
location until you turn them off, allowing you to watch what
your program is doing to those memory locations.

* If you have an 8087 or 287 floating-point chip, D86 will
generate complete window of the 87 state. The values of the
stack elements are in a readable decimal format, with
suppression of unneccessary zeroes, and scientific notation
only if necessary.

* You can, at any time, enable a help-window, to guide you
through debugger commands. You will be astounded by the
sophistication of this help-facility, especially since other
debuggers offer no on-line help whatsoever.

* All of the above-mentioned windows, except for the last two,
exist on the screen at the same time. You don't have to switch
between them.
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* You can single-step your program with single keystrokes, rather
than sequences of arcane commands. There are several flavors
of single-step keys, clustered together on the function-keypad.
This, combined with the automatic nature of the display, allows
you to single-step very quickly. You feel like you are
actually watching your program run.

* Much of D86's command language is simply the A86 assembly
language itself. You can type in any A86 instruction, to be
executed immediately. You use this to set registers and
variables, perform arithmetic, jump to another location, etc.
The immediate-execution feature makes D86 the most effective
tool available for teaching 86 architecture: the student can
watch the effects of instructions on registers, flags, and
memory.

* You can patch programs in memory, using the full power of the
A86 assembly language.


How to Contact Me

I have no plans to move from my present location at least through
the millennium. So you can write to:

Eric Isaacson Software
416 East University Ave.
Bloomington, IN 47401-4739

or call (812)339-1811.

Sorry, I can't guarantee to return everybody's long distance
calls. If you'd like to be SURE I'll get back to you, please
invite me to call you back collect, or tell me to charge the cost
of the call to your credit card.

I also have a section on Compuserve: just type GO ZIPKEY to any !
prompt. (ZIPKEY is the name of my other product line, a pop-up
zipcode directory.) My Internet address is
[email protected].

PLEASE contact me if you find bugs in my programs; I'll fix them!
I accept bug reports from anyone, registered or non-registered,
no questions asked. It's very frustrating to hear about people
telling each other about bugs, and not telling me. I still await
Greg Wettstein's bug list.