Loaded and Linker
Duration: 3 min
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The lecture focuses on the concept of relocatable machine code within the context of a language processing system. The instructor explains that this type of code can be loaded at any memory point and run, with addresses designed to cooperate with program movement. A detailed diagram illustrates the steps from High-Level Language (HLL) through preprocessing, compilation, and assembly to the final target machine code. The instructor uses a specific if-else logic example to demonstrate how assembly code uses relative jumps to handle control flow without fixed absolute addresses. Presented by Sanchit Jain Sir from Knowledge Gate Educator.
Chapters
0:00 – 2:00 00:00-02:00
The instructor begins by defining Relocatable Machine Code using a slide that highlights its ability to be loaded at any point. He references a vertical flowchart showing the Steps in a Language Processing System, tracing the path from HLL down to Machine Code (Relocatable) produced by the Assembler. To clarify the concept, he writes out assembly instructions for a conditional statement, underlining specific lines like if (a<b) goto (i+3) and i+2) goto (i+4) to show how the program flow jumps between relative offsets rather than fixed memory locations. He explicitly points out the lines i+1) t=0 and i+3) t=1 to show the assignment logic.
2:00 – 3:22 02:00-03:22
The session transitions to the roles of the Linker and Loader. The slide explains that these tools convert relocatable code into absolute code, preparing it for execution. A flowchart visualizes the process: Source Program -> Assembler -> Object Program -> Linker -> Executable Code -> Loader -> Memory. The instructor briefly displays assembly code for a for loop to reinforce the concept of relative addressing in loops. Finally, he introduces Compiler Design, presenting a slide that divides the compiler into an Analysis phase (Front-end) and a Synthesis phase (Back-end), listing components like the Lexical Analyzer, Syntax Analyzer, and Code Optimiser. He underlines the text Linker loads a variety of object files into a single file to make it executable.
The lesson effectively bridges the gap between low-level code generation and system execution. It starts by defining the flexibility of relocatable code and how assembly instructions manage relative jumps. It then explains the necessary system utilities (linker/loader) that finalize the code for the CPU. The lecture concludes by contextualizing these steps within the broader architecture of a compiler, separating the understanding of source code (analysis) from the generation of target code (synthesis).