entc 349 week 3 - session 3 program design calculator

2012 Texas A&M Univesity 1

ENTC 349 Week 3 – Session 3Calculator Design & Example Program

George B. WrightSenior LecturerElectronics & TelecommunicationsEngineering Technology

Texas A&M Univesity 2

Topics

ReviewProject DesignProgram ExampleDevelopment – Input

Input Hierarchy ChartInput Flow ChartsInput Code

Program Example

test.asm


* Test Program - ARM Assembly on TMS570* Programmer - George B. Wright

.armSTART mov r0,#1

mov r1,#2add r1,r1,r0str r1,sum

EXIT b EXIT

sum .set 0.end

Assembly Language Options

In-line assemblyCommand line environment with standalone tools, Assembler, linker, loader, debugger, etc.Integrated Development Environment


How do I Assemble this code.


Command Line View

DOS Window


Editor View of .asm


Editor View of .lst


Command Line Assembly



Objectives

Expand our knowledge of Program DesignExpand our knowledge of the ARM RCPU Instruction Set –TMS570Design a Four Function Calculator using the Texas Instruments RCPU as implemented on the TMS570 family RCPU’s.


Project Design Review

Program SpecificationBlock Diagram - HardwareFunctional DescriptionHierarchy Chart (s)Flow Chart (s)Pseudo CodeCode

AssemblyC or a combination of the these languages


A Starting Point for the Design

Calculator

Initialize Input Calc Output

Problem – Design a four function calculator using the TMS570 microcontorller.

1. Functionally decompose the problem into components.

2. Create a hierarchy chart that show the relationship between the components/functions.


Four Function Integer Calculator

Calculator

Initialize Input Calc Output Exit

getoperand getoperator

getchar

chkchar

getchar

chkchar

operanderror operatorerror

Hierarchy Chart


Functional Design

A functional design typically includes two components

Functional RequirementsPerformance Requirements

A functional requirement is typically stated in functional terms

For the calculator design a function would be - Input


Functional Requirement - Input

The calculator must accept integer input expressed as ASCII characters from a keyboard or sixteen key keypad.The format of the input is as follows

>Calculator>1+2=3>

.

Where the bold characters areentered by the operator and allothers are displayed by the program

Presenter

Presentation Notes

Pick up on the input format and discuss the syntax > [operand] operator [operand] terminal character Relate the syntax to the hierarchy chart.


Input Syntax

>1+2=3 The bold characters are entered by the operator.

The format is as follows:> 1 + 2 =

Prompt Operand Operator Operand Terminator


Input Hierarchy Chart

Input

getoperand getoperator inputerror

getchar chkchar operanderror getchar checkoper opererror


Flow Chart - getoperand

Here is our first try.Will this design do the job?


Problem - getoperand

It only handles single character operands!It does not handle operators?Error handling?This subroutine needs to be refined.


Assembly Language Code

Where do you start coding?Higher level functions or lower level function? High Level

What is the purpose of high level functions?

To perform program ControlWhat is the purpose of low level functions?

To get the work done


Function LevelCalculator

Initialize Input Output Exit

getoperand getoperator

getchar

chkchar

getchar

chkchar

operanderror operatorerror

0

1

2

3


Calculator Level 0

Calculator FunctionalityCode format

Calculator LoopInput

bl INITLOOP bl INPUT

bl CALCbl OUTPUTb LOOP

INPUT bl GETOPERANDbl GETOPERATORbl GETOPERANDmov pc,lr


What is down the road?

Exam 1 two weeks from today. Next Friday, one week before the exam

Problem Set 1 AssignedReview Sheet

Expand knowledge of Instruction SetExpand assembly language programming skill and knowledge


What is next?

Expand the calculator code.Prepare by developing your version.We will look at the details.

Hierarchy ChartFlow ChartsCode


References

Knaggs, P., Welsh, S. ARM Assembly Language Programming, July 2008.Hohl, William, ARM Assembly Language: Fundamentals and Techniques, CRC Press, 2009.


Revised - getoperand

Is this any better?


Is this it?

entc 349 week 3 - session 3 program design calculator

Documents

functional design

input format

integer input

input syntax1

knowledge of program

function calculator

functional terms

texas instruments rcpu