1. Business Programming I
Fall – 2000 By
Jim Payne

2. Jim Payne - University of Tulsa
Babbage to Billy-O
Between 1833 and the mid-1940’s, there were very few new developments in the field of programming languages. We did see a major contribution to the future of computing with the development of the keypunch machine and punch cards by Herman Hollerith in the 1880’s.
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Jim Payne - University of Tulsa

3. Jim Payne - University of Tulsa
Tabulating Machine
Link to biography of Herman Hollerith
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Jim Payne - University of Tulsa

4. Links: Early History of Computers
Virginia Tech – History of Computing
Virtual Museum of the United Kingdom
Smithsonian Museum - Computers
Check out these sites to learn more about the Turing Machine, the ABC machine, the ENIAC, and then in 1951, the UNIVAC. All of these machines were either hard wired for each instruction or began the use of assembler language instructions.
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Jim Payne - University of Tulsa

5. Jim Payne - University of Tulsa
Assembler Language
In the slides that follow, I will be using an “assembler like” computer programming language named BILLY-O. The language was developed at Iowa State University and then used by Dr. Roger Wainwright – TU, for several years in the early 1980’s to support the teaching of programming concepts and to help students understand at least the basics of what actually happens inside the computer.
My thanks to Dr. Wainwright for supporting its continued use some twenty years later. 
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Jim Payne - University of Tulsa

6. Instructions: I/O & Memory Movement
INP Input
OUT Output
LDA Load Accumulator
STA Store Accumulator
LDC Load a Constant
ADC Add a Constant
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Jim Payne - University of Tulsa

7. Instructions: Arithmetic Operators
ADD Add to Accumulator
SUB Subtract from Accumulator
MPY Multiply Accumulator
DIV Divide Accumulator
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Jim Payne - University of Tulsa

8. Instructions: Branching Commands
BRU Branch Unconditionally
BPA Branch + Accumulator
BNA Branch - Accumulator
BZA Branch Zero Accumulator
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Jim Payne - University of Tulsa

9. Instructions: Data and Ending
HLT End of Procedure
NUM Initializing Variables
END Last Instruction
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Jim Payne - University of Tulsa

10. BILLY-O LANGUAGE Complete Instruction Set
INP
OUT
LDA
STA
LDC
ADC
ADD
SUB
MPY
DIV
BRU
BPA
BNA
BZA
HLT
NUM
END
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Jim Payne - University of Tulsa

11. INP Memory ADC LDC LDA OUT BRU BPA BNA BZA Accumulator STA
ADD
SUB
MPY
DIV
Accumulator
STA
Arithmetic Logic Unit

12. Problem: Input 2 numbers, A & B. Compute C = A * B. Then Output C.
Answer: C = 30
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Jim Payne - University of Tulsa

13. FLOWCHART OF PROBLEM
START
INP A
INP B
LDA A
MPY B
STA C
C = A * B
OUT C
STOP

14. 1 2 3 4 5 6 7 8 9 I N P A B L D M Y S T C O U H E

15. INP Arithmetic Logic Unit Accumulator Memory OUT ADC LDC LDA STA BRU
ADD
SUB
MPY
DIV
STA
BRU
BPA
BNA
BZA
5,6 A B C
INP A
INP B
LDA A
MPY B
STA C
OUT C
HLT
END 5 6 30 30 5 30

16. Jim Payne - University of Tulsa
Problem:
Input a series of exam scores between 0 and 100 until a trip value of 999 is entered.
Then print out the number of scores processed, the average exam score, and the number of students that passed the exam (score of 60 or better).
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Jim Payne - University of Tulsa

17. Introduction of Bertha’s DP World
Typewriter
Calculator
Paper & Pencil IN
OUT

18. How Would Bertha Do This?
Pick Up from the in basket a series of exam scores between 0 and 100 until a trip value of 999 is encountered.
Then type up a report that provides the number of scores processed, the average exam score, and the number of students that passed the exam (score of 60 or better).
Then put the typed report in the out basket.
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Jim Payne - University of Tulsa

19. STEPS: (In Pseudocode Form)
Bertha Method
Sum of Scores
Counter of Scores
Counter of Passing
IN Basket 70 80
100 40 10
999
STEPS: (In Pseudocode Form)
Pick up a card from the in basket.
If score = 999, do what? Else do what?
NOT EQUAL 999: Add score to Sum of Scores, Add 1 to Counter of Scores. If score >= 60, Add 1 to Counter of Passing. Then go read next score.
EQUAL 999: Compute Average Score = Sum of Scores / Counter of Scores. Print out report answers. Quit Processing

20. Variable Naming SCR = Individual Score SOS = Sum of Scores
COS = Counter of Scores
COP = Counter of Passing
AVG = Average Score = SOS / COS

21. Pseudocode Revised Flowchart of Logic Input a value for SCR
Start
Stop
Input a value for SCR
If SCR = 999
Compute AVG = SOS / COS
Print Results and Quit
Else
Compute SOS = SOS + SCR
Compute COS = COS + 1
If SCR >= 60
Compute COP = COP + 1
EndIf
Endif
Go to Top of Program

22. Billy-O Program TOP INP SCR LDA SCR ADC -999 BZA MID LDA SOS ADD SCR
STA SOS
LDA COS
ADC 1
STA COS
ADC -60
BNA TOP
LDA COP
STA COP
BRU TOP
MID LDA SOS
DIV COS
STA AVG
OUT AVG
OUT COS
OUT COP
HLT
SOS NUM 0
COS NUM 0
COP NUM 0
END

23. Billy-O Program IN Basket 70 80 100 40 10 999 TOP INP SCR LDA SCR
ADC -999
BZA MID
LDA SOS
ADD SCR
STA SOS
LDA COS
ADC 1
STA COS
ADC -60
BNA TOP
LDA COP
STA COP
BRU TOP
MID LDA SOS
DIV COS
STA AVG
OUT AVG
OUT COS
OUT COP
HLT
SOS NUM 0
COS NUM 0
COP NUM 0
END
IN Basket 70 80
100 40 10
999

24. Jim Payne - University of Tulsa
Go TU !!!
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Jim Payne - University of Tulsa