Business Programming I

Fall – 2000By

Jim Payne

Lecture 02 Jim Payne - University of Tulsa 2

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.

Lecture 02 Jim Payne - University of Tulsa 3

Tabulating Machine

Link to biography of Herman Hollerith

Lecture 02 Jim Payne - University of Tulsa 4

Links: Early History of Computers

Virginia Tech – History of ComputingVirtual Museum of the United KingdomSmithsonian Museum - ComputersCheck 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.

Lecture 02 Jim Payne - University of Tulsa 5

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.

Lecture 02 Jim Payne - University of Tulsa 6

Instructions: I/O & Memory Movement

INP InputOUT OutputLDA Load Accumulator STA Store AccumulatorLDC Load a ConstantADC Add a Constant

Lecture 02 Jim Payne - University of Tulsa 7

Instructions: Arithmetic

Operators

ADD Add to AccumulatorSUB Subtract from AccumulatorMPY Multiply AccumulatorDIV Divide Accumulator

Lecture 02 Jim Payne - University of Tulsa 8

Instructions: Branching Commands

BRU Branch UnconditionallyBPA Branch + AccumulatorBNA Branch - AccumulatorBZA Branch Zero Accumulator

Lecture 02 Jim Payne - University of Tulsa 9

Instructions: Data and Ending

HLT End of ProcedureNUM Initializing VariablesEND Last Instruction

Lecture 02 Jim Payne - University of Tulsa 10

BILLY-O LANGUAGEComplete Instruction Set

INP OUT LDA STA

LDC ADC ADD SUB

MPY DIV BRU BPA

BNA BZA HLT NUM

END

INP

Arithmetic Logic Unit

Accumulator

Memory

OUT

ADC LDC LDA

ADD

SUB

MPY

DIV

STA

BRU

BPA

BNA

BZA

Lecture 02 Jim Payne - University of Tulsa 12

Problem: Input 2 numbers, A & B. Compute C = A * B.Then Output C.

A = 5 B = 6

Answer: C = 30

FLOWCHART OF PROBLEM

START

INP A

INP B

C = A * B

OUT C

STOP

LDA A

MPY B

STA C

1 2 3 4 5 6 7 8 9

I N P A

I N P B

L D A A

M P Y B

S T A C

O U T C

H L T

E N D

INP

Arithmetic Logic Unit

Accumulator

Memory

OUT

ADC LDC LDA

ADD

SUB

MPY

DIV

STA

BRU

BPA

BNA

BZA

5,6

ABC

INP A

INP B

LDA A

MPY B

STA C

OUT C

HLT

END

56

5

30

30

30

Lecture 02 Jim Payne - University of Tulsa 16

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).

Introduction of Bertha’s DP World

IN OUT

Typewriter

Calculator

Paper & Pencil

Lecture 02 Jim Payne - University of Tulsa 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.

Bertha Method

IN Baske

t

70

80

100

40

10

999

Sum of Scores

Counter of Scores

Counter of Passing

0 00

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

Variable Naming

SCR = Individual Score

SOS = Sum of Scores

COS = Counter of Scores

COP = Counter of Passing

AVG = Average Score = SOS / COS

Pseudocode Revised

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

Flowchart of Logic

Start

Stop

Billy-O Program

TOP INP SCR

LDA SCR

ADC -999

BZA MID

LDA SOS

ADD SCR

STA SOS

LDA COS

ADC 1

STA COS

LDA SCR

ADC -60

BNA TOP

LDA COP

ADC 1

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

Billy-O Program

TOP INP SCR

LDA SCR

ADC -999

BZA MID

LDA SOS

ADD SCR

STA SOS

LDA COS

ADC 1

STA COS

LDA SCR

ADC -60

BNA TOP

LDA COP

ADC 1

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 Baske

t

70

80

100

40

10

999

Lecture 02 Jim Payne - University of Tulsa 24