Chapter 5- Assembling , Linking, and Executing Programs Lecture 3 Chapter 5- Assembling , Linking, and Executing Programs

Lecture Outline Creating and Running a Program Step1: Creating the Source Program File Step2: Assembling & Linking the Program Step3: Running the Program 1

Creating and Running a Program A text editor or word processor is used to create a source program file. Editor .ASM file An assembler is used to translate the source file into a machine language object file. Assembler .OBJ file A linker is used to link one or more object files to create a run file. Linker .EXE file 2

Creating and Running a Program Assembling: translate source program (written in assembly language) into machine code (object code) Linking: complete machine code for the object program, generate an executable module

Step 2: Assembling & Linking the program After printing the copyright information, the assembler will check the source file for syntax errors: If one or more errors were found: The assembler will display the line number of each error and a short description. If no errors were found: The assembler will translate the assembly language code into the assembly machine language object file (.obj file). The linker will take one or more object files, fills any missing addresses, and combines the object files into a single executable file (.exe file). 6