SPACE Newsletter

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Minutes of Space meeting December 08, 1995

- NEWSLETTER January, 1996 President's Corner By Mike Fitzpatrick As you are all aware the weather forced a cancellation of the Christmas Party. Many thanks to: Rich Mier. Ray Wafer. Greg Leitner. and others who passed the word along. Also, we had help from KOOL-I 08 and WCCO radio in getting the message out over the radio waves. The plan is to have a party at the January meeting. Please try to bring what you signed up for plus a little bit for yourself. The sheet cake that we picked up was well received by all our neighbors at our impromptu snow removal party the night of the canceled SPACE meeting. The method <maximum frustration> of contacting folks was exacerbated by the loss of the BBS, with all the member records, two days prior to the meeting. Hopefully that will never happen again. I do think that a calling plan for a member daisy chain of contacting might be a point to consider. Here's hoping that you had a great Holiday Season and 1996 will be filled with Health, Happiness, and Prosperity to you all. There is one item that I'll save for Lance to discuss in January about new developments for the classic Atari 8-bit computer.

It was the night before the Space annual Christmas party and all through the house, nothing was stirring except me. I was busy preparing the big 13-pound turkey for our Christmas party, Friday, December 8, I995. I put it in the oven to cook over night. In the morning I pulled a delicious looking turkey out of the oven. I then put it in the ice box. In the evening I was going to add it to all the delicious food at the party. You all know the rest, the club party was canceled by MOTHER NATURE. Luckily we have a chance to celebrate a Christmas party at our January 12, 1996 meeting. We can also include celebrating a new year. For al] members that signed up to bring something on the Christmas potluck list, please bring food in for the Christmas party in January. Be prepared to have a fun time tool The rnidv.~nter Madness show is rapidly approaching. It will be hdd on February 10, i 995 at Blaine Sports Center in Blaine. Be sure to bring plenty of money because there will probably be plenty of bargains. Last of all, because we didn't have a club meeting in December because of MOTHER NATURE, there aren't any minutes to report. See you at the January Space meeting, and be prepared to PARTY HARDY and FEAST LIKE KINGS! Michael Weist Club Secretary

SPACE'S 13TH CHRISTMAS PARTY POTLUCK SIGN-UP LIST

BBS Report

PERSON

As you know the BBS went down on the 6th of December. A REALLY honible event. The problem with the BBS was the hard drive. The older l'\-ITM & RLL drives were warranted for 500 hours of service life. Well in six months time 4500 hr's is the norm. This will be an increasingly growing problem as those types of drives are only available as used; true condition unknown. For the technical folks: a post mortem on the drive indicated that the bearing(s) lost the permanent lub. Friction and heat did the rest. Imbedded SCSrs are available but they tend to be expensive. I would also save that type of drive for the ST where the full potential ofthe drive can be utilized. It appears that I was able to save the user dat file so that few if any had to re-log on. There is still a minor problem with the 3rd party f-mail and I plan on working that out with K-Products and Steve Cardin (BBS Express-Pro programmer). As of this writing the files have not been reloaded but the plan is to do it on Superbowl Sunday when few if any will be bbsing.

Terry Streeter Mike Fitzpatrick

POTLUCK ITEM

chicken salad cake meat tray veggies Salad Meatballs 48 cans pop Special K Bars BBQ Smookies Cookies

Greg Leinter J. Overbaugh D. Wold Bill Cotter Glen Kirschenmann Al Noble Don Langford Lance Ringquist ??????????? Larry Serflatten Potatoe salad Ray Wafer ???????????? Mike Weist Mike Schmidt Plates, napkins, utensils

+----------------------------------------+ I Larry's I

: irst the fl owchart:

I ACTION! TUTORIAL I +---------------------------------------- + #17 VICTORY

1. 2. 3. 4. 5. 6. 7. 8. 9.

From the last issue: The 12 different boxes of product need 11 gates to provide 12 c o nveyors to the 12 automatic shelves. My set of eleven tests began with a scale weighing out any package less than 15 Lbs. If your solution has something different, that is perfectly acceptable, provided it meets the needs of the job. Basica l ly the first test should divide the gr oup of products roughly in half, but it is no t mandatory. The important part is that it perfo rms as required, and you can check that by using your flowchart to see where each box would get diverted t o . The criteria was that the boxes should end up on separate shelves. Yo u might imagine the supervisor may want to inves t mo re c a sh into the system and ask you to add in the needed equipment to reject certain boxes which fail in a unique way, and return all rejects on a new conveyor to the plant. Such is the way it goes in prc grammi ng, just when you think your done, somebody shows up and wants to change the program. A good flowchart helps in modifying an already complete program. Wi~h a flow chart, the programmer can make necessary changes to the algorithm, and can quickly add in the needed code in the proper spot. This is just a reminder to always document your programs, either by the use of a flow chart, or in the source code itself. You never know when you may decide to add more stuff to a finished program . Moving from words in a flowchart, to code on the computer can be made easy to do. The more details included in a flowchart, the easier it is to translate into code . Flowcharts also help in optimization of algorithms. Careful inspection of a flow chart can reveal redundant loading of a variable, or testing of a value, that may be consolidated or reduced. Looking at the whole process, might give insight to a different algorithm, or method, that will do the same thing even quicker. Some times a better algorithm will be enough, and should be attempted first, but there are occasions when assembly is the best choice. Remember you need only to rework the code that causes a delay, or that will make a perceptable difference. There is no big advantage in optimizing the part of a program that is already performing well. As if to fly in the face of go od advice, look back at issue #12's procedures. Here we had a few good routines that were made even better by translating part of them to machine code (AscToint). EchcS has a loop in it, one of the most basic programming structures, and the most time consuming. Translating this routine to machine code will provide an example of the loop structure as it appears in machine language .

Save STRING address Calc ulate DESTINATION address Initialize counter Load byte from STRING Save byte to DESTINATION Decrement counter Test for end condition Loop to "4" until done RETURN

Now the code: PROC EchoS=*(BYTE ARRAYS) ;1. Save STRING address ($85 $A2 ;STA $A2 Save S LO $86 $A3 ;STX $A3 Save SHI ;2. DEST=(Y*40)+SAVMSC+X $AS $54 ;LDA $54 Y pos $A2 40 ;LDX #40 $20 MultiplyB ; J SR MultiplyB $18 ;CLC $AS $58 ;LDA $58 Screen LO $65 $55 ;ADC $55 X pos ;ADC $AO $65 $AO (Y*40) LO $85 $A4 ;STA $A3 DEST LO $A5 $59 ;LDA $59 Screen HI $65 $Al ;ADC $Al (Y*40) HI $85 $A5 ;STA $A4 DEST HI ;3. Init counter $AO $00 ;LDY 0 $Bl $A2 ;LDA ($A2),Y $AS ;TAY $88 ;DEY ;START=START+l S(0) is string Length ! $18 ;CLC $E6 $A2 ;INC $A2 $DO $02 ;BNE 2 $E6 $A3 ;INC $A3 ;4. LOOP start, load byte $Bl $A2 ;LDA ($A2),Y $20 AscToint ;JSR AscToint ;5. Store byte $91 $A4 ;STA ($A4),Y ;6. Decrement counter $88 ;DEY ; 7 & 8. Test and Loop until done $10 $F6 ;BPL (LOOP) ;9. RETURN from whence we came $60] ; RETURN As you can see, most ot tnis procedure is spent setting up the parameters for the loop. The loop itself is quite small, only 10 bytes (Two bytes are used to indicate where AscToint is located). This loop can still be optimized further, if desired, by moving all the code from the AscToint routi ne to its proper place in the loop. This results in eliminating the need for jumping (using time to store values on the processor stack and in the program counter) which is time consuming when done repeatedly. The code from the AscToint routine is needed for this loop to function , so moving it 'in line' will make the loop larger, but will actually reduce the execution time. Were you wondering how to call a procedure using machine language? You can also call ACTION! routines that you have written. ACTION! passes variables using the A and X registers, and returns function values in $AO and $Al.

+----------------------------------------+ I Larry's I I I ACTION! TUTORIAL +----------------------------------------+ #18 BREAKING THE RECORD! BYTES, CARDS, POINTERS, and ARRAYS can be used for most of your programming. There comes a time when you must work with a large amount of data, and a mixed set of BYTES, CARDS, and ARRAYS. At times it makes sense to organize your data so that it may be easily processed, other times it makes just as much sense to organize your data for optimum use with files on a disk. Records are used to help in both of these areas. Records allow a programmer to group the fundamental data types together (BYTES, CARDS, and INTEGERS). The grouping must be declared before it is used. 'l'he records become real useful when you set up a block of memory to hold an array of records. This is no more than a BYTE array, which is divided into individual records, one record right after the other. Each record can be accessed using a record POINTER, which steps through the array, in steps the size of one record. TYPE DAY=[BYTE hi,lo ;Record FORMAT INT change] BYTE ARRAY memory(400) ;Records storage DAY POINTER temp

;Record ID

DEFINE RECORD SIZE="4" ;2 BYTES+ 1 INT ; 99 max! DEFINE MAX DAYS=" 9" PROC Make Record() BYTE i,r=53770,oldtemp INT chg temp=memory

;# la

oldtemp=75 FOR i= 0 TO ~.AX DAYS DO chg=r&7 chg==-4 temp.change=chg temp.hi=oldtemp+chg temp.lo=temp.hi-5-(r&3) oldtemp=temp .hi temp==+RECORD_SIZE ;# lb OD RETURN PROC SHON () BYTE i Make_Record () Graphics( 0) PrintE(" " ) ·

printE ( "DAY

High

Low

Chg")

FOR i=0 TO MAX DAYS DO temp=memory+(RECORD SIZE*i) ;# 2 PrintF(" %U %U %U %I " , i,temp.hi,temp.lo,temp.change) PrintE(" " ) OD RETURN You can read your manual to get further information on declaring records. This program is nothing special, it creates a list of each days high and low temperature and indica~es the change of the high temp from one day to the next. Take note, there are two methods used to access the records. Method #1 sets 'temp ' to the start of the storage area (la) and steps through each record by adding RECORD SIZE to 'temp' (lb) each pass through the-loop. Method #2 calculates the proper location of each record (#2) . This random access method of l ocating each record is simple to use and works well for records t hat reside completely in memory. Because each record can be accessed in a uniform manner, the need for special data handling code is reduced. To give you a little practice in using records, try to write a routine that would allow you to enter the data for this program. You can have the user input the high and low temperatures, and the computer calculating the amount of change in high temperature from the previous day. When you have that routine working , write a program to keep track of the time of the sun rising and settbrg each day. Also keep track of how many hours of daylight there are in each day and the change in daylight hours from one day to the next. The more practice you get, the better you become . Records are a very useful tool . As will be shown next month, they can be used to provide an easy means of working with data objects (the manual calls them 'virtual records') , we're going to call them worms!

CLUB OFFICIALS President: Vice President: Secretar y: DOM Librarian: Paper Librarian: Software Librarian: Membership Chairman: SPACE Treasurer SPACE Newsletter Editor:

Mike Fitzpatrick Terry Streeter Mike Wiest (Temp) Terry Streeter Vacant Earline Fitzpatrick Glen Kirschenma nn Greg Leitner Michael Schmidt

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786-4790 455-6550 757-4192

Saint Paul Atari Computer Enthusias ts {SPACE)

Published by the Saint Paul Atari Computer Enthusiasts (SPACE). an independen t organization with no business affiliation with ATARI Corporation . Permission is granted to any similar or ganization with wh ich SPACE exchanges newsletters to reprint material from this newsletter. We do however ask that credit be given to the authors and to SPACE. Opinions expressed are those of the authors and do not n ecessarily reflect the views of SPACE, the club officers. club members or ATARI Corporation.

meets on the second Friday of each month al 7:30 PM

in the Falcon Heights Communi ty Center at

2077 West Larpenteur Ave. Doors open at 7:00 PM.

Falcon Heights Community Center 2077 W. Larpenteur Ave.

Gibbs Museum

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Larpenteu r Avenue

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SPACE BBS

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BBS Phone: (612)- 427-43 17 ;

Sysop: Mike Fitzpa trick Co-sys op: Open Positio n Suppor ting:

U of M St. Paul Campus

S.P.A.C.E. P.O . Box 120016 Nevr Bright on , MN

ATARI 8-Bit Compu te~s ATARI ST Comp uters

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55112

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