prog develop tools

8/4/2019 Prog Develop Tools

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PROGRAMDEVELOPMENT

TOOLS


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INTRODUCTION

Program development is a process of program design,development, implementation, translation, testing,debugging and maintenance. The availability of righttools makes the program development process easier.The program development tools includes the following

1. Text Editor 7. Debugger2. Pre-processor 8. EXE-to-COM Converter3. Assembler 9. Library Builder4. Complier 10. Emulators5. Linker

6. Loader


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1. TEXT EDITOR

Text Editor is defined as a software that allows the userto enter program and modify the program. Theprogram created using text editor is known as sourceprogram. The editor provides a set of commands for

insertion, deletion, modification of a single letter,statement, or block of statements etc. The text editormodel is shown in fig -1. Some examples of editors are

Norton Editor (NE), DOS Editor (EDIT), Visual Editor(VI) etc.


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1. TEXT EDITOR

UsercommandsNew or Old

Text File

Creation and modifications of ASCII

Text files and source files. Information Movements between files. Programmers source code editor.

SourceProgram

Examples NE, VI, EDIT, QNE etc.

TEXT EDITOR

(hello.asm)old

(hello.asm)Updated

Fig -1


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2. PRE-PROCESSOR

Pre-processor is software that translates a sourceprogram with macros and includes header files to thesource files with the macros resolved and header filesincluded in the source program. The pre-processorsoutput is then transferred to the next phase of theprogram translation. Generally, pre-processors are builtinto the assemblers or the compliers. It is also called asthe macroprocessor. The model of a preprocessor is

shown in fig -2. Some examples of pre-processor arebuilt-in Borlands Turbo assembler (TASM),Microsofts Macro assembler (MASM), High Level

Language Compilers such as Borland C, Microsoft Cetc.


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2. PRE-PROCESSOR

SourceProgram

Replaces Macros andincludes Header files

Inform Macro errors.Source file

With macrosresolved

Examples Part of translators TASM,MASM etc.

PRE-PROCESSOR

Transfers toNext phase of Translator

(hello.asm)or(hello.c)

Fig -2


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3. ASSEMBLER

Assembler is a software that translates assemblylanguage program to a machine language program. The

input to the assembler is known as a source file. Theassembler produces the output as relocatable objectcode. It reports program errors during translation. The

model of an assembler is shown in fig -3. someexamples of assemblers are Borlands Turbo assembler(TASM), Microsofts Macro assembler (MASM), etc.


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3. ASSEMBLER

AssemblyProgram

Converts assembly programsto relocatable object code.

Inform program errors.Object

Program

Examples TASM,MASM etc.

ASSEMBLER

(hello.asm) hello.obj

Fig -3


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4. COMPILER

Compiler is a software that translates high levellanguage program to an equivalent object code in a

relocatable code. The input to the compiler is a sourcefile. The compiler produces the output as relocatableobject code. It reports program errors during

translation. The model of a compiler is shown in fig -4.some examples of compilers are Borland or Microsoftcompiler for C, Turbo Pascal, WATFOR forFORTON, etc.


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4. COMPILER

High levelLanguageProgram

Converts High level language programs

to assembly code or relocatableobject code. Inform program errors.

ObjectProgram

Examples TC, BC, BCC, CL, FL, etc.

COMPILER

(hello.c) hello.obj

Fig -4


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5. LINKER

Linker is a software that combines relocatable objectprogram modules and library functions into an

executable file. It combines library functionsreferenced in the program and other program modulesand produces a single executable file. It resolves the

external symbols (variables) referenced in a modulewhich is defined in other modules. It reports linkingerrors if external symbols cannot be resolved. Themodel of a linker is shown in fig -5. Some examples of linkers are Borlands Turbo linker (TLINK),Microsofts linker (LINK), etc.


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5. LINKER

Objectfile(s)

Combines object files, library modulesand creates a relocatable executable file Executablefile

Examples TLINK, LINK, etc.

LINKER

(hello.obj) hello.exe

Fig -5


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6. LOADER

Loader is a software that loads the executable fileproduced by a linker into the main memory for

execution. After loading the program in main memory,the loader transfers control to the program forexecution. The model of a loader is shown in fig -6.

The Operating System shell functions as a loader, theMS-DOS shell COMMAND.COM is an example of loader.


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6. LOADER

ExecutableProgram

Loads program in the main memory

for execution.Executable

file

Examples SHELL, COMMAND.COM, etc.

LOADER

(hello.exe)

After execution, control isReturned to the loaderFig -6


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7. DEBUGGER

Debugger is a software that allows the execution of aprogram in single step mode under control of the user.

The process of locating and correcting an error using adebugger is known as debugging. A debugger executethe object program generated by an assembler or

complier with debug options. The debuggers thatfacilitates program debugging at source level areknown as source level debugger. The debuggersprovide single stepping, break point, and programtracking facility. The model of a debugger is shown infig -7. Some examples of debugger are BorlandsTurbo debugger (TD), Code View (CV), etc.


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7. DEBUGGER

ExecutableProgram

Source level debugging. Single step & Break point execution. CPU status at any time. Data modification at run time.

ProgramBugsIdentified

Examples TD, CV, DEBUG etc.

DEBUGGER

(hello.exe)

Fig -7


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8. EXE TO COM CONVERTER

EXE to COM converter is a software that convertsexecutable file (EXE) to a command file (COM) The

model of a EXE to COM converter is shown in fig -8.Some examples of EXE to COM are MicrosoftsEXEBIN utility, Borlands Turbo linker with tiny

memory model option (TLINL / T), etc.


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8. EXE TO COM CONVERTER

ExecutableProgram

Translates executable file to memoryimage file which requires no additionalrelocation.

MemoryImage

Executablefile

Examples TLINK / T, EXE2BIN, etc.

COM GENERATOR

(hello.exe) (hello.com)

Fig -8


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9. LIBRARY BUILDER

Library builder is a software that combines all theprogram modules into a single file known as library.

The library can be shared by multiple users forprogram development. It includes very frequently usedfunctions. The compiler developers supply the built-in

functions in the form of a library. The model of alibrary builder is shown in fig -9. Some examples of library builder are Microsofts LiB, Borlands TLiButilities, etc.


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9. LIBRARY BUILDER

ProgramModules inExecutable

Object form

Combines all the program modules intoa single library file

Library fileFile.lib

Examples TLINK / T, EXE2BIN, etc.

LIBRARY BUILDER

P1.obj, p2.obj, etc. Program.lib

Fig -9


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10. EMULATORS

An emulator is a mixture of hardware and software. Itis usually used to test and debug the hardware and

software of an external system such as the prototype of a microprocessor based instrument. Part of thehardware of an emulator is a multiwire cable which

connects the host system to the system beingdeveloped. A plug at the end of the cable is pluggedinto the prototype system in place of itsmicroprocessor. Through this connection the softwareof the emulator allows you to download your objectcode program into RAM in the system being tested andrun it.


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10. EMULATORS

Like a debugger, an emulator allows you to load andrun programs, examine and change the contents of registers, examine and change the contents of memory

locations, and insert breakpoints in the program. Theemulator also takes a snapshots of the contents of registers, activity on the address and data bus, and stateof flags as each instruction executes. The emulatorstores this trace data in a large RAM. You can printoutof the trace data to see the results that your programproduced on a step-by-step basis.

Another powerful feature of an emulator is the ability

to use either system memory or the memory on theprototype for the program you are debugging


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PROGRAM DEVELOPMENT PROCESS

Program development is a process of program design,development, implementation, translation, testing,debugging and maintenance of the program. It is aninteractive and iterative process which involves thefollowing steps

1. Source file creation2. Object code generation3. Executable file creation4. Program running5. Program testing

6. Program debugging



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Borland C has program development environmentknown as Integrated Development Environment (IDE).It is a menu driver environment from which thedevelopment tools can be invoked. The programdevelopment process is illustrated in fig -10. TheBorland program development tools are used inexplaining the program development process.

START


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Program Editing

Create or Modify program(Editor)

Assemble/Compile Program

(Assembler/Compiler)

Create Executable file(Linker)

Run Program

(Loader)

Debugging to detect

Program errors (Debugger)

Assembly/CompileErrors ?

Result Satisfactory ?

Linking Errors ? STOP

Source file

Relocatable object file

Yes

Yes

No

No

No

Yes

NoFig -10



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1. Source file creation: The file containing programstatements in assembly or high level language is

known as a source file. The source file is created andedited using text editor. The assembly language sourcefile has an extension .ASM and C language source filehas an extension .C file. The C source file can becreated in an integrated program development editor.



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2. Object code generation: The language translators areused to translate source program into a relocatable

object file. The assembler is used in the translation of assembly language source code and the compiler isused in translation of high level language source such

as C program. The assembler/compiler generates .objfile if no errors are encountered during translation.3. Executable file creation: Linker is used to create

executable files. The some linkers are used totranslates assembly and C language object file intoexecutable files. The assembler/compiler generates

.exe file if no errors are encountered during linking.



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4. Program running: The executable files can run byentering the name of the executable file as followsc > helloac > helloc

5. Program testing: The results generated by theprogram have to be tested for their validity. The resultmust confirm to the program specification. If there areany errors in the result, then the program has to bedebugged.



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6. Program debugging: The errors in the program canbe located using debugger. The executable file of theprogram to be debugged must be created with theprogram debug options. The Turbo assembler use /ZIoption and linker uses /v option to create an executablefile which can be debugged at the source level.

Note:

Program development process must be repeated untilthe program works according to the specification.

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