Macro-Processors-and-Compilers_Unit-II.pptx
- 1. Macro Processors and Compilers Macros offer a powerful way to define reusable code blocks. Compilers bridge the gap between high-level languages and machine code, making programming easier and more efficient. Prepared by : Prof. Neelam Jadhav
- 2. Introduction to Macro Processing Macros are a powerful tool for code reusability and abstraction, allowing developers to define code snippets that can be expanded into larger code blocks. 1 Macro Instruction Arguments Arguments allow macros to be parameterized, making them more flexible and adaptable to different situations. 2 Conditional Macro Expansion Conditional expansion allows macros to behave differently based on specific conditions, adding logic to code generation. 3 Macro Calls Within Macros Nested macro calls enable complex and hierarchical code structures, further enhancing the power of macros. 4 Macro Definitions Macros are defined with a name and a body, which contains the code that will be expanded when the macro is called.
- 3. Designing Macro Processors Macro processors are responsible for expanding macro definitions into actual code during the compilation process, ensuring that the code is correct and efficient. 1 Pass 1 This pass reads the source program and builds a macro definition table, which stores all the defined macros and their associated code. 2 Pass 2 This pass reads the source program again, expanding all macro calls based on the definitions stored in the macro definition table. 3 Output The output of the macro processor is a program with all the macro calls expanded, ready for further compilation.
- 4. The Single Pass Macro Processor A single-pass macro processor aims to expand macros during a single pass through the source program, improving efficiency and reducing the overall compilation time. Advantages Simpler implementation, faster execution, can handle macros defined within other macros. Disadvantages Limited functionality, cannot handle recursive macro definitions, may require complex data structures.
- 5. Introduction to Compilers Compilers are essential software tools that translate high-level programming languages into machine code, allowing computers to understand and execute programs written in various languages. Lexical Analysis This phase scans the source code and breaks it down into basic tokens, such as keywords, identifiers, and operators. Syntax Analysis This phase checks the syntactic correctness of the source code, ensuring it follows the grammatical rules of the programming language. Semantic Analysis This phase analyzes the meaning of the source code, checking for type compatibility and other semantic errors. Intermediate Code Generation This phase translates the source code into an intermediate representation, which is closer to machine code but still platform- independent. Code Optimization This phase aims to improve the efficiency of the generated code by removing redundant code, reducing the size, and improving performance.
- 6. Benefits of Assembly Language Assembly language offers low-level control over hardware, allowing developers to optimize programs for specific architectures, but it comes at the cost of readability and portability. Direct Hardware Access Assembly language provides direct access to memory locations, registers, and other hardware components, offering granular control over system resources. Efficiency Assembly language allows developers to write code that is highly optimized for specific hardware, leading to increased speed and efficiency. Debugging Assembly language code can be easily debugged and analyzed, as each instruction directly corresponds to a specific machine operation.
- 7. Assembly Language: Structure and Design Assembly language programs consist of a set of instructions that operate on data stored in memory locations, registers, and other hardware components. Label Instruction Operand START MOV AX, 10 ADD AX, BX END HLT
- 8. Two-Pass Assembler Design A two-pass assembler processes the source program twice, building a symbol table in the first pass and generating machine code in the second pass. 1 Pass 1 This pass scans the source program, identifying labels and their corresponding addresses, and building a symbol table that maps labels to their memory locations. 2 Pass 2 This pass reads the source program again, using the symbol table to resolve labels and generate the final machine code, which can be executed by the computer. 3 Output The output of the assembler is an object code file, containing the machine code generated from the assembly language source program.
- 9. Compilers vs. Interpreters Both compilers and interpreters translate high-level code into executable instructions. Compilers translate the entire program at once, while interpreters execute code line by line. Compilers Fast execution, optimized code, well-suited for large projects. Interpreters More flexible, easier debugging, well-suited for interactive development.