882 lines
23 KiB
Plaintext
882 lines
23 KiB
Plaintext
|
|
***********************************
|
|
Zmagazine June 11, 1986
|
|
^^^ New Jersey Edition
|
|
HOT Atari News Plus+++
|
|
Ron Kovacs-Editor, Middlesex, NJ
|
|
***********************************
|
|
XxIn this Issue
|
|
Zmag BBS Watch
|
|
|
|
Mouse for your 8 bit???
|
|
|
|
Part One of a series on Assembly
|
|
Language programming
|
|
|
|
Special BBS comment
|
|
|
|
Zmag Notes
|
|
-----------------------------------
|
|
XxCommodore 1350 Controller for
|
|
your Atari!!!
|
|
|
|
THE COMMODORE 1350 CONTROLLER
|
|
FOR YOUR ATARI!(Or The Mouse That
|
|
Jack Built) by Jay Pierstorff
|
|
|
|
There has been much talk of
|
|
mice and mouse controllers lately.
|
|
The new Atari ST's come equipped
|
|
with their own mouse...(mice?)
|
|
..meeces?. Anyway, those of us who
|
|
have an Atari of the 8-bit
|
|
persuasion have watched with
|
|
great envy, wishing we too, could
|
|
have mice. Even if we could buy an
|
|
ST mouse for our 8-bitters (which
|
|
we can't) it wouldn't work with our
|
|
existing joystuck (sic) programs.
|
|
Sure, we'd all love to have an
|
|
Atari ST, but my 130XE's library
|
|
is bigger than the ST's and more
|
|
important, it's paid for.
|
|
|
|
Atari is rumored to be
|
|
introducing an 8-bit mouse, but it
|
|
is not confirmed at the time this
|
|
article is being written. Mouse
|
|
envy persists. I found myself
|
|
wandering the aisles of the
|
|
computer stores. Suddenly,I noticed
|
|
a Commodore product beaming through
|
|
the glass. -The Commodore 1350
|
|
Mouse for the C128- was printed on
|
|
the package. The price was less
|
|
than $50. Those lucky 128 owners!
|
|
Too bad Atari hasn't made one for
|
|
their computers.
|
|
|
|
The C128 Commodore is an
|
|
upwardly compatible to the C64
|
|
computer. That means that any
|
|
software that worked on the 64 will
|
|
also run on the 128. The C64 and
|
|
the Atari's have always been real
|
|
friendly about using the same
|
|
joystick varieties. Would this....
|
|
could this... might this mouse work
|
|
with a trackball or mouse driver
|
|
program? The plug looked very much
|
|
like a standard joystick connector.
|
|
I bought it antook it home.
|
|
|
|
I could tell my Atari 130XE was
|
|
nervous about the whole works, but
|
|
undaunted, I loaded a trackball
|
|
program, plugged in the mouse...
|
|
but wait, the plug would not stay
|
|
in! Upon close examination of the
|
|
connector, I discovered that it was
|
|
about 1/8 of an inch too short to
|
|
reach the connector pins,
|
|
(Commodore computers don't recess
|
|
their joystick ports quite as much
|
|
as Atari). I was Puzzled for a
|
|
moment and then I thought about
|
|
using a joystick extension cable!
|
|
Ha! I quickly found my extension
|
|
cable and plugged one end into port
|
|
1 and the other end plugged
|
|
perfectly to the mouse!
|
|
|
|
With trembling fingers I slid
|
|
the mouse across the desk, and
|
|
then... nothing. The cursor was on
|
|
the screen but the mouse yawned. It
|
|
would not control the cursor, not
|
|
even a little. Now what... I tried
|
|
to think, maybe it would work with
|
|
a Koala or Touch Tablet program! I
|
|
booted and failed.
|
|
|
|
Maybe it was a -joystk
|
|
emulator!- A Joystick in mouse
|
|
clothing! I loaded the graphics
|
|
editor of The Print Shop, IT WORKED
|
|
IT WAS A JOYSTICK EMULATOR ALL
|
|
ALONG! Suddenly, it occurred to me
|
|
I should probably calm down. I got
|
|
down off the computer table and
|
|
tried a few more programs.
|
|
Everything that would normally run
|
|
with a joystick, was working with
|
|
this imitation mouse.
|
|
|
|
A comparison of the mouse and
|
|
the Atari port shows the
|
|
connections are mostly compatible
|
|
with Atari and Commodore joysticks.
|
|
Interesting that the brief, mouse
|
|
instructions made no mention of
|
|
Joystick emulation or even
|
|
compatibility with the C64! Strange
|
|
thing to keep a secret! Especially
|
|
for companies in business to make
|
|
money (right Jack?).
|
|
|
|
The only non-workable feature
|
|
of the 1350 Mouse is the right
|
|
button. The left button is the
|
|
standard -fire- button on a
|
|
Joystick. The right button is
|
|
connected to pin 9. The Atari looks
|
|
to pin 9 for a potentiometer
|
|
reading like a paddle controller
|
|
would pruce. But since their is
|
|
no paddle emulation in the mouse,
|
|
the right button is invisible to
|
|
the Atari's OS. Oh well, one
|
|
doesn't miss what one has never
|
|
had. If Joysticks were meant to
|
|
have two buttons....well you know
|
|
what I mean.
|
|
|
|
The Commodore Mouse is very
|
|
usable. Even though your computer
|
|
thinks it's a joystick, you will
|
|
think it's a mouse! It really does
|
|
an amazing job of convincing you!
|
|
It feels good in your hand and
|
|
moves smoothly across any flat
|
|
surface. A clean desk or a -mouse
|
|
pad- will give best results. A
|
|
mouse pad is a rubber backed thin
|
|
cushion that gives more control
|
|
over mouse movements. For mouse
|
|
maintenance, the rubber-coated,
|
|
steel ball can be easily removed
|
|
for cleaning.
|
|
|
|
The 1350 Mouse is different
|
|
from a true optical driven mouse.
|
|
A true mouse has proportional
|
|
control. The faster you move the
|
|
mouse, the faster the cursor will
|
|
move. The 1350 mimics this action
|
|
but it can't move the cursor any
|
|
faster than a joystick would.
|
|
Slower cursor movements are
|
|
imitated by the mouse delivering
|
|
short, stop and go pulses to the
|
|
computer.
|
|
|
|
A true mouse will always take
|
|
the same desktop travel to move the
|
|
cursor from one screen edge to the
|
|
other. The 1350 will move the
|
|
cursor at maximum speed as long as
|
|
the 1350 is in any motion at any
|
|
speed. That means a fast, long push
|
|
may not move the cursor as far as a
|
|
short, slow push! That's not really
|
|
a problem though, it's just a
|
|
difference that can be worked with.
|
|
It can even be an advantage for
|
|
limited desktop space.
|
|
|
|
The Commodore 1350 Mouse
|
|
worked with all games and programs
|
|
that require a joystick. Some are
|
|
improved by the mouse and some are
|
|
more suited to joystick control.
|
|
The type of programs that are best
|
|
suited to the mouse are those that
|
|
require precision movements of
|
|
cursor or gunsight centering on the
|
|
screen. The least suited are the
|
|
programs reqring continuous
|
|
scrolling movementsThey often
|
|
require picking the mouse up and
|
|
starting again if you run out of
|
|
counter space. Drawing and doodling
|
|
programs worked fabulous, Koronis
|
|
Rift scores improved markedly,
|
|
Rescue on Fractalus was confusing!
|
|
Donkey Kong was ...different! It
|
|
just depends on the type of
|
|
movement involved. Many games took
|
|
on a whole new feel when played
|
|
with the mouse. Many were even more
|
|
fun with a mouse than with a
|
|
joystick!
|
|
|
|
Do you really need a mouse?
|
|
Yes you do! If you own and use a
|
|
joystick, you will definitely
|
|
enjoy owning a 1350 mouse. I
|
|
wouldn't part with mine. Don't
|
|
throw your joystick away yet, but
|
|
mine is seeing less use since I let
|
|
the mouse in the house! The
|
|
Commodore mouse is not just for the
|
|
C128 anymore! It's one of the best
|
|
darn joysticks since the old Atari
|
|
licorice stick!
|
|
|
|
XxZmag BBS Watch
|
|
Messages captured from the Windy
|
|
City BBCS in Chicago. Home of
|
|
Clinton Smith, Chicago Zmag Editor
|
|
|
|
Board :ATARI ST SIG
|
|
Date & Time :06/02/86 06:28:46
|
|
Subject :CPM
|
|
To :ALL
|
|
Sent by :SYSOP
|
|
|
|
THE CPM SOFTWARE EMULATOR FOR THE
|
|
ST IS READY AND IT SHOULD BE OUT IN
|
|
THE FALL..........
|
|
|
|
Board :ATARI RUMORS
|
|
Date & Time :06/02/86 06:31:15
|
|
Subject :3 1/2 DRVS.
|
|
To :ALL
|
|
Sent by :SYSOP
|
|
|
|
THEY ARE COMMING 3 1/2-DRIVES FOR
|
|
THE 8 BIT LINE LATE THIS YEAR OR
|
|
EARLY NEXT BUT THEY WILL BE
|
|
RELEASED....
|
|
|
|
Board :ZMAG MESG BASE
|
|
Date & Time :06/02/86 10:56:42
|
|
Subject :ZMAG IN JERSEY
|
|
To :RON KOVACS (REC)
|
|
Sent by :CLINTON SMITH
|
|
|
|
|
|
THE MESSAGE BASE GOT WIPED OUT,SO
|
|
IN CASE YOU DIDN'T GET MY RESPONSE
|
|
I'M REPEATING IT.YOU HAVE ZMAG UP
|
|
ON 6 BOARDS IN NEW JERSEY?I'M
|
|
IMPRESSED.WE JUST REACHED THAT
|
|
HERE,AND WE'VE BEEN AROUND FOR 6
|
|
MONTHS.WHEN YOU'RE UP ON COMPU
|
|
SERVE,BE SURE TO LEAVE A MSG. FOR
|
|
TIM OROSZ.HE'S A BIG HELP WITH
|
|
ZMAG OUT HERE.HE'S GOING TO BE
|
|
GETTING THE ANTIC ONLINE REPORTS,
|
|
BUT THANKS FOR THE OFFER ANYWAY.
|
|
ONE OF THEYSOPS OF WINDY,WROTE
|
|
UP A PIECE ON CES,HE WAS THERE
|
|
|
|
|
|
Board :ZMAG MESG BASE
|
|
Date & Time :06/02/86 12:03:54
|
|
Subject :ZMAG IN JERSEY CONT
|
|
To :RON KOVACS (REC)
|
|
Sent by :CLINTON SMITH
|
|
|
|
SUNDAY.KIND OF A LOCAL PERSPECTIVE
|
|
ON CES.CONCERNING COMPUSERVE MSG,
|
|
IF YOU SEE SOMETHING OF IMPORTANCE
|
|
JUST GIVE THE INFO FROM THE MSG.
|
|
IF YOU REALLY WANT TO REPRINT THE
|
|
EXACT MSG. I SUPPOSE YOU COULD ASK
|
|
THE PERSON FOR PERMISSION.I DON'T
|
|
THINK THE ATTORNIES COULD SWARM
|
|
DOWN ON US IN THAT SITUATION.I AM
|
|
INTERESTED IN THE SCOTT B.
|
|
INTERVIEW.BE HEARING FROM YOU.
|
|
CLINTON SMITH
|
|
ZMAG EDITOR
|
|
P.S. TOMMOROW NIGHT IS THE SPECIAL
|
|
CLAUG MEETING WITH ATARI EXECS.
|
|
MAYBE THIS COULD RETURN THE FAVOR
|
|
ON THE INTERVIEW.
|
|
|
|
Board :ZMAG MESG BASE
|
|
Date & Time :06/02/86 11:08:38
|
|
Subject :SPECIAL MEETING
|
|
To :ALL
|
|
Sent by :CLINTON SMITH
|
|
|
|
I'VE BEEN GIVING THE REGULAR
|
|
CLAUG MEETING ACE AT TRITON,IN
|
|
REFERENCE TO THE SPECIAL MEETING
|
|
TOMMOROW.I FOUND OUT FROM GERRY
|
|
FEID ON BLUE MOON,THAT IS GOING
|
|
TO BE IN THE IRONWOOD ROOM.SAME
|
|
BUILDING,EXCEPT THIS ROOM IS ON
|
|
FIRST FLOOR.I THINK IT IS RIGHT
|
|
ACROSS FROM THE BURGER KING THAT
|
|
IS IN THE BUILDING.BE THERE BEFORE
|
|
8PM OTHERWISE YOU WON'T BE LET
|
|
IN.
|
|
CLINTON SMITH
|
|
ZMAG EDITOR
|
|
|
|
Board :ATARI ST SIG
|
|
Date & Time :06/02/86 14:22:08
|
|
Subject :SEE ONE!
|
|
To :ALL
|
|
Sent by :TOM ZUREK
|
|
|
|
Hi Guys & Gals,
|
|
Were would the nearest place be
|
|
that I could take a look at one of
|
|
these ST's.... I own a couple 8
|
|
bits but haven't seen an ST yet.
|
|
I live on the NW side of
|
|
Chicago....
|
|
Thanx, Tom Zurek
|
|
|
|
XxZmag Newz
|
|
Zmag debuts on another local BBS
|
|
System.
|
|
Backstage DOWNLOAD DIRECTORY
|
|
FILENAME TRANSLATE SECS TYPE LANG
|
|
___________________________________
|
|
LDBNDT21 ATASCII 0127 Comm Bas
|
|
EXPR1030 ATASCII 0263 Comm Obj
|
|
COPYXE ATASCII 0012 Util Obj
|
|
DEBUG ATASCII 0048 Util Obj
|
|
DARTS ATASCII 0111 Ga Bas
|
|
SHRINK ATASCII 0032 Util Obj
|
|
ZMAG604 ATASCII 0129 TEXT NEW
|
|
[D]ownload [N]ext Page [M]ain Menu:
|
|
|
|
Thanks to The Director, Sysop of
|
|
The Backstage BBS. Previewed last
|
|
week here in Zmag in a BBS Review
|
|
by Walt.
|
|
201-944-1196
|
|
Welcome!!!!
|
|
|
|
Messages captured from the Valhalla
|
|
BBS. 212-598-0243
|
|
|
|
MSG#: 1621 Lines=16 Recv
|
|
SENT:JUNE 10,1986 AT 10:03 PM
|
|
TO: WODEN-SYSOP
|
|
FROM:RICHARD SCHRAUDNER
|
|
SUBJ:TEXPRO
|
|
|
|
---WODEN---
|
|
Zmag seems to be a GREAT idea.
|
|
When I think back to my early atari
|
|
days, up all night keying in
|
|
Compute programs & now fully
|
|
immersed in the -mainstream- of
|
|
computer technology, I'm amazed at
|
|
the oportunitues to learn & enjoy.
|
|
Zmag seems to fill an additional
|
|
void that goes beyond an individual
|
|
board or even network. I'll D/L
|
|
some more as time allows & get it
|
|
up to the Fun house (a bit hard to
|
|
get to during available hours). Thx
|
|
& looking forward actually meeting.
|
|
---rs---
|
|
|
|
MSG#: 1604 Lines=30 Recv
|
|
SENT: JUNE 9, 1986
|
|
TO: SCARFACE
|
|
FROM:RATBANE
|
|
SUBJ:ZMAG
|
|
|
|
HI,
|
|
IF YOU LET ME KNOW WHAT YOU ARE
|
|
LOOKING FOR, I CAN TARGET STUFF
|
|
TO YOUR NEEDS AND WANTS. IF
|
|
SOMETHING IS SLIGHTLY OFF-TARGET,
|
|
LET ME KNOW. IT IS ONLY A MILD
|
|
PROBLEM FOR ME TO WRITE 2 VERSIONS
|
|
OF SOMETHING--ONE FOR THE ATOMIC
|
|
AUDIENCE AND ONE FOR ZMAG READERS.
|
|
DOES ZMAG WANT PUBLIC SERVICE
|
|
ANNOUNCEMENTS? DOES ZMAG WANT
|
|
NEWS WHICH HAS NOTHING TO DO WITH
|
|
COMPUTERS, BUT SETS AN EXAMPLE OF
|
|
WHAT COMPUTER BBS CAN PUT UP FOR
|
|
GENERAL CONSUMPTION (E.G. MOST OF
|
|
WHAT I HAVE WRITTEN)? WOULD
|
|
ZMAG BE INTERESTED IN EXAMPLES OF
|
|
LOCAL NEWS WHICH MIGHT SOUND
|
|
EXOTIC TO FOREIGNERS, SAY, FROM
|
|
THE MIDWEST OR CALIFORNIA? I
|
|
HAVE IN MIND THE STATUE OF
|
|
LIBERTY CELEBRATIONS. IF WE PUT
|
|
OUR COMPUTER TO USE FOR SOME
|
|
LOCAL ORGANIZATION WOULD YOU BE
|
|
INTERESTED IN A WRIEUP, AGA AS
|
|
AN EXAMPLE OF WHAT COMPUTER BBS
|
|
CAN DO? THESE IDEAS ARE WHERE MY
|
|
NERAL INCLINATION LIES. DO LET
|
|
ME KNOW.
|
|
WARMEST REGARDS,
|
|
|
|
MSG#: 1600 Lines=16 Recv
|
|
SENT:JUNE 8,1986 AT 8:35 AM
|
|
TO: RICHARD SCHRAUDNER
|
|
FROM:WODEN-SYSOP
|
|
SUBJ:TEXPRO
|
|
|
|
RON CAN EXPLAIN ZMAG BETTER THEN
|
|
I COULD RICHARD, BUT LET ME TO
|
|
SHED SOME LIGHT TILL RON LOGS ON.
|
|
ZMAG IS A MAGAZINE FOR THE
|
|
BULLETIN BOARDS. AS I UNTERSTAND
|
|
IT, IT WAS STARTED BY SOMEONE IN
|
|
CHICAGO. RON IS THE EDITOR FOR
|
|
ZMAG FOR THE LOCAL AREA. THE
|
|
MATERIAL COMES FROM USERS OF
|
|
BULLETIN BOARDS AND COMPUSERVE.
|
|
IT BRINGS UP TO THE MINUTE NEWS
|
|
OF EVENTS, COMPUTERS AND OTHER
|
|
SUBJECTS. I THINK THAT IT IS A VERY
|
|
GOOD IDEA. DON'T YOU?
|
|
WODEN
|
|
|
|
XxAssembly Language Course
|
|
This is part of a series. Next week
|
|
part 2.
|
|
|
|
ANTIC PUBLISHING INC., COPYRIGHT
|
|
1985. REPRINTED BY PERMISSION.
|
|
|
|
CHRIS CRAWFORD
|
|
ASSEMBLY LANGUAGE COURSE
|
|
FOR WORLDWIDE USERS NETWORK
|
|
|
|
Assembly language is the great
|
|
barrier that divides the
|
|
professional programmer from the
|
|
amateur. It is the most powerful
|
|
language available for a
|
|
microcomputer.
|
|
|
|
There are four reasons for
|
|
learning to program in assembly
|
|
language. First, the speed of
|
|
execution of assembly language is
|
|
very high -- about ten time higher
|
|
than BASIC on the average, perhaps
|
|
a thousand times faster on certain
|
|
operations.
|
|
|
|
Even ACTION, the fastest
|
|
high-level language, is only about
|
|
half as fast as assembly language.
|
|
Second, assembly language tends to
|
|
be more compact than many
|
|
languages. Again, ACTION! provides
|
|
a good comparison. Code produced by
|
|
ACTION! is about twice as large as
|
|
equivalent assembly language.
|
|
|
|
The third reason to program in
|
|
assembly language is that assembly
|
|
gives you access to features of the
|
|
machine that simply are not
|
|
available in high-level languages.
|
|
Interrupts are the most notable
|
|
examples.
|
|
|
|
Finally, the most important
|
|
reason for learning to program in
|
|
assembly language is thait will
|
|
help you to understand the machine
|
|
better. And that is a very good
|
|
place to begin, for you cannot
|
|
learn assembly language unless you
|
|
know a little bit about computers.
|
|
|
|
HOW COMPUTERS WORK
|
|
|
|
I am now going to describe how
|
|
computers work, in very rough
|
|
terms. Computers operate on a
|
|
hierarchy of concepts that spans a
|
|
great range, rather like the
|
|
hierarchy that starts with
|
|
protons and electrons, moves
|
|
through atoms, molecules, cells,
|
|
people to civilizations.
|
|
|
|
A civilization is composed of
|
|
protons and electrons, but to
|
|
understand how it is so composed
|
|
one must know a great deal about
|
|
the intermediate steps. So too is
|
|
a computer composed of transistors.
|
|
There are four intermediate steps
|
|
between the transistor and the
|
|
computer.
|
|
|
|
A transistor is an electrically
|
|
operated switch. We can assemble
|
|
transistors into gates that will
|
|
turn circuits on or off depending
|
|
on the states of other circuits.
|
|
There are a variety of gates
|
|
reflecting the various Boolean
|
|
operations: AND, OR, NOT, NAND, NOR
|
|
and EOR.
|
|
|
|
Gates can be assembled into
|
|
latches, decoders, and adders. A
|
|
latch is the simplest memory
|
|
element: it remembers one bit of
|
|
information. A decoder translates
|
|
a number encoded in binary form on
|
|
a few wires into a selection of one
|
|
of many wires. An adder will add
|
|
two one-bit values, with a carry,
|
|
and generate a carry of its own.
|
|
|
|
We can next broaden each of
|
|
these devices into an eight-bit
|
|
device by simply slinging the
|
|
devices side by side. Eight one-
|
|
bit latches slung side-by-the side
|
|
give one byte of RAM. Eight
|
|
adders make an eight-bit adder.
|
|
|
|
We can thus create a RAM module
|
|
by building many butes of RAM. We
|
|
access this RAM module with three
|
|
buses: a data bus, an address bus,
|
|
and a control bus. The data bus
|
|
carries information between the
|
|
central processing unit and the RAM
|
|
module.
|
|
|
|
The address bus is sixteen bits
|
|
wide; a decoder inhe RAM module.
|
|
The address bus is sixteen bits
|
|
wide; a decoder in the RAM module
|
|
takes the numeric value on the
|
|
address bus and decodes it to
|
|
select the single byte of RAM that
|
|
is indicated by the address. The
|
|
control bus establishes the
|
|
direction of the data flow on the
|
|
data bus and the timing of data
|
|
transfer.
|
|
|
|
The central processing unit
|
|
(CPU) represents the highest
|
|
intellectual level of the computer.
|
|
It is composed of four parts: the
|
|
Arithmetic and Logic Unit (ALU),
|
|
the registers, the address bus
|
|
controller, and the instruction
|
|
decoder. The ALU is composed of
|
|
adders and gate arrays that crunch
|
|
numbers. The particular device to
|
|
use is selected with a decoder.
|
|
|
|
The registers are simply on-
|
|
board RAM. The address bus
|
|
controller is a device that puts
|
|
the desired RAM address onto the
|
|
address bus. The real heart of the
|
|
CPU is the instruction decoder, a
|
|
very complex decoder that takes the
|
|
program instructions out of RAM and
|
|
translates them into action. It
|
|
does this by feeding the
|
|
instructions (which are numbers)
|
|
into decoder circuits that activate
|
|
the desired gateways in the CPU.
|
|
|
|
PROGRAMMING A MICROPROCESSOR
|
|
|
|
Machine code is nothing more
|
|
than a bunch of numbers that mean
|
|
something to the CPU. It's hard to
|
|
work with pure numbers, so we use a
|
|
little code that makes it easier
|
|
for us to understand the codes that
|
|
the computer uses. This programmer
|
|
-friendlier code is called assembly
|
|
language, It is a direct, one-to-
|
|
one translation of machine code.
|
|
Here is an example of the two side
|
|
by side:
|
|
|
|
Machine Code Assembly
|
|
Language
|
|
|
|
A9 05 LDA #FINGERS
|
|
133 $9C STA COUNT
|
|
|
|
The code on the right may not
|
|
look very readable, but you must
|
|
agree, it's far more readable than
|
|
the code on the left. And they
|
|
both mean exactlthe same thing.
|
|
|
|
Unfortunately, the computer
|
|
cannot read the assembly code, only
|
|
the machine code. Thefore, we
|
|
need a translator program that will
|
|
translate the easier-to-understand
|
|
code on the right into the
|
|
impossible-to-understand code on
|
|
the left. This translator program
|
|
is called an assembler.
|
|
|
|
A program that goes in the
|
|
reverse direction, translating
|
|
machine code to assembly, is called
|
|
disassembler. It may seem like a
|
|
bother to go through all the hassle
|
|
of using an assembler, but it is
|
|
actually much easier.
|
|
|
|
Assembly language is not only
|
|
more readable than machine code,
|
|
but it is also assembly-time
|
|
relocatable; this means you can
|
|
move it around in RAM freely before
|
|
you start the assembly process. A
|
|
good assembler also offers a number
|
|
of extra features that make it
|
|
easier to keep track of your
|
|
program or modify it quickly.
|
|
|
|
USING AN ASSEMBLER
|
|
|
|
There are three steps involved
|
|
in writing an assembly language
|
|
program: editing, assembling, and
|
|
debugging. Editing is the process
|
|
of typing in your assembly language
|
|
statements. Assembling is the
|
|
invocation of the assembler.
|
|
Debugging is the process of running
|
|
your program and analyzing why it
|
|
doesn't work. Thus, the entire
|
|
process of writing an assembly-
|
|
language process can be described
|
|
by a fictitious BASIC program:
|
|
|
|
FOR 1= 1 to 1,000,000,000...
|
|
EDIT PROGRAM
|
|
ASSEMBLE PROGRAM
|
|
DEBUG PROGRAM
|
|
NEXT 1
|
|
|
|
THE 6502 MICROPROCESSOR
|
|
|
|
The first item in the 6502 that
|
|
I will describe is the accumulator.
|
|
This is a single one-byte register
|
|
in the 6502. It is the central
|
|
workbench of the microprocessor;
|
|
almost everything happens in the
|
|
accumulator. Your first three
|
|
instructions on the 6502 are:
|
|
|
|
LDA address (Load the
|
|
Accumulator with the contents of
|
|
address)
|
|
|
|
This instruction loads the
|
|
accumulator with the contents of
|
|
the memory location specified by
|
|
the value of address. The address
|
|
can be specified by either an out-
|
|
right value, such as $0600, or a
|
|
symbolic reference, such as FISH,
|
|
ere the value of FISH has been
|
|
previously declared by, say, an ORG
|
|
statement or an equate statement.
|
|
|
|
LDA #value (Load the Accumulator
|
|
with value)
|
|
|
|
This is much like the earlier
|
|
statment; it loads the accumulator
|
|
with a number, only the number
|
|
loaded is specified immediately
|
|
rather than stored in a memory
|
|
location. Thus, the command LDA # 9
|
|
will put a 9 into the accumulator.
|
|
|
|
STA address (Store the
|
|
Accumulator into address)
|
|
|
|
This command will store the
|
|
contents of the accumulator into
|
|
the RAM location whose address is
|
|
specified in the command. It is
|
|
just like the first command, except
|
|
that the direction of data motion
|
|
is reversed. The LDA command is
|
|
like a read, which the STA is like
|
|
a write.
|
|
|
|
You are now equipped to move
|
|
data around inside the computer.
|
|
These commands will allow you to
|
|
readata from one area of memory
|
|
and store it into another. LDA and
|
|
STA are the two most common
|
|
instructions used in any 6502
|
|
program.
|
|
|
|
Exercise: Write a program that
|
|
will read the contents of address
|
|
$FE00 and store the result into
|
|
address $680. Your biggest problem
|
|
here will be just getting your
|
|
assembler to work. Therefore, I
|
|
will give the answer away:
|
|
|
|
ROMADD ORG $FE00
|
|
RAMADD ORG $680
|
|
ORG $600
|
|
LDA ROMADD
|
|
STA RAMADD
|
|
BRK
|
|
END
|
|
|
|
That's the program. Try to get it
|
|
running with your assembler.
|
|
|
|
|
|
[Next Week: Part 2 of this series]
|
|
|
|
XxBBS Rewview
|
|
By:Walt Drummond
|
|
|
|
|
|
BBS Review
|
|
|
|
This week, I'm giving the review
|
|
to Ron Kovacs, SysOp of The Syndicate
|
|
BBS, because he was having a problem
|
|
with one of his Users, or Abu, in this
|
|
case. Ron and I think ALL Users should
|
|
share his experences, and see what a
|
|
SysOp has to put up with.
|
|
Heres Ron->
|
|
|
|
I have thought about putting the
|
|
following text in Zmag for about
|
|
3 days. After all this pondering
|
|
I decided I would extract the bad
|
|
language and let you see what a
|
|
us on my BBS thinks of some of
|
|
the changes made on the BBS. Due
|
|
to the length and the language left
|
|
in the text I have trimmed it down.
|
|
|
|
Board :SYSOP
|
|
Message # :243
|
|
Date & Time :06/08/86 23:27:26
|
|
Subject :HELP/OPINION
|
|
To :SYSOP
|
|
Sent by :THE SOCIALIST
|
|
|
|
First of all you must have some
|
|
weird control stuff in your main
|
|
menu which is screwing me over
|
|
something bad over here... Jus'
|
|
doesn't look right in ASCII.
|
|
|
|
Now for the -who asked you?- Depar-
|
|
tment. Very honestly, I think this
|
|
BBS is going downhill and I think
|
|
something should be done about it!
|
|
First off, why cant you be indepe-
|
|
ntdant? Why must you be in a big
|
|
interstate network, have a big
|
|
interstate magazine extending all
|
|
the way to Chicago, and be so
|
|
damn stuck up.............I mean,
|
|
you're still the same but you seem
|
|
to want to jump on the bandwagon,
|
|
and as a result this BBS isnt just
|
|
a BBS, it is a collection of BBS's
|
|
all the way around the tri-state
|
|
area. I am beginning to feel like
|
|
I'm on some big timesharing thing
|
|
like Compuserve or something. My
|
|
suggestion, drop the whole thing
|
|
and stop catering to all these
|
|
stupid BBS's and user groups. I
|
|
have never heard of BAT, or even
|
|
BAUD, before a month or so ago.
|
|
And I don't care. I also don't
|
|
care wut BBS's are in this great
|
|
Atomic Network which in my opinion
|
|
is a fluke...............
|
|
- - - - - - - - - - - - - - - - - -
|
|
I am sure you all get the picture
|
|
of this text. Now I will respond
|
|
with my opinion. I feel that
|
|
grouping good systems and people
|
|
together is a great thing to do.
|
|
Expanding one's horizons and
|
|
looking around you is the best way
|
|
to keep learning and knowing what
|
|
is going on. To stay 100% local
|
|
means you are shutting yourself out
|
|
and not opening up for new ideas.
|
|
I intend to connue advertising
|
|
Zmag where ever I can, get these
|
|
local systems interested and get
|
|
a group of people together who want
|
|
to work together at someing
|
|
more interesting than playing
|
|
games all day. I feel that what has
|
|
been accomplished so far is proof
|
|
that users want more than reading
|
|
messages and seeing things like
|
|
you read. If I had the room and
|
|
the guts to print the exact wording
|
|
you would see what the other users
|
|
did. However, this will never
|
|
happen here. I want to thank the
|
|
many people who have offered their
|
|
assistance for the summer, and the
|
|
SysOps who have joined the fast
|
|
growing Zmag family. I am sure
|
|
there are many SysOps out there who
|
|
have received many messages like
|
|
this one and I think I will do a
|
|
future edition on the subject.
|
|
|
|
Thanks to Walt for the space and
|
|
the positive response in this
|
|
matter.
|
|
|
|
XxZmag Notes
|
|
Next week I will have a short text
|
|
with some comments from Scott
|
|
Brause about Sourceview. And a
|
|
few other topics.
|
|
|
|
Part 2 in our continuing series
|
|
on Assembly language programming.
|
|
|
|
News from The Brooklyn Atari Team
|
|
newsletter.
|
|
|
|
BBS Review returns with another
|
|
review from Walt Drummond.
|
|
|
|
BBS Watch, ST NEWS, and more....
|
|
|
|
See you next week.
|
|
-----------------------------------
|
|
Zmagazine Vol 1 No.4 June 11, 1986
|
|
NEXT ISSUE June 18, 1986.
|
|
Please contribute. NJ Edition
|
|
-----------------------------------
|