Assembler Compiler Interpreter Lecture Overview Assembler Compiler Interpreter

Assembler, Compiler, Interpreter

Lecture Overview • Assembler • Compiler • Interpreter

ASSEMBLER

Assembler • To convert the assembly language into machine code. • Translate mnemonic operation codes to their machine language equivalents. • Assigning machine addresses to symbolic labels.

Assembler Directives • The assembler can also process assembler directives. • Assembler directives (or pseudoinstructions) provide instructions to the assembler itself. They are not translated into machine instructions • E. g. • START (specify name and starting address for the program). • END (indicate the end of the source program and (optionally) specify the first executable instruction in the program)

Working of Assembler • Programmer write a program using a sequence of assemble instructions. • This sequence of assembler instructions, known as the source code/source program, then specified to the assembler program when that program is started. • It translates a source code into machine language. • The output of the assembler program is called the object code or object program.

COMPILER

Compiler • A program that changes source code (highlevel language) to object code which that can be executed by a machine. • Compiler: o Checks syntax of program o Checks at a time all the program • Primary reason for compiling source code is to create an executable program • Examples of compiler based language: • C, C++, JAVA

Executables • Executables: Files that actually do something by carrying out a set of instructions. • E. g. , . exe files in Windows • Once the executable is there, it can be called by the user to process the given inputs to a program and produce the desired outputs.

Example of Compiler • Some of examples of Compiler: o Microsoft Visual Studio o Blue. J o Quincy 2005 • We use C++ programming language.

INTERPRETER

Interpreter • A computer program that executes instructions written in a programming language and do not produces the executable file. • Interpreter: o Checks the keywords of a program o Taking one instruction at a time and convert it into machine language before taking upon the next instruction. • Examples of interpreter based language: o PHP, Java. Script, BASIC

Compiler vs. Interpreter

Example of Interpreter • We use Java. Script language. • Java. Script engine is specialized computer software which interprets and executes Java. Script. Mostly used in web browsers.

Summary • Assembler = To convert the assembly language into machine code. • Compiler = A program that changes source code (high-level language) to object code which that can be executed by a machine. • A computer program that executes instructions written in a programming language and do not produces the executable file.