Machine & Assembly Language

• Languages and Translators deal with how human-readable instructions are converted into machine-executable code

Machine Code

• Written in binary
• Each instruction performs a small task
• Programming is difficult and time-consuming
• Is a low-level language

Assembly Language

• Allows programmers to create programs more easily than with machine code
• Is processor-specific
• Each assembly language instruction maps directly to machine code
• Needs translation to machine code before execution
• There is a 1:1 correspondence between assembly language and machine code
• An assembler is a program that translates assembly language into machine code
• Is a low-level language
• Assembly code example: "LDA 51" means load the contents of memory location 51 into the accumulator, add hexadecimal value FF, and store the result in location 52. The machine code equivalent is "1000101100000100001001010011001"

Processors

• Can only execute instructions in machine code
• There are many types: Intel i7, Apple A13 Bionic
• Machine code instructions are specific to a processor family
• Programs written for a PC cannot run on Apple or Samsung devices

Assembly Language Uses

• Used in embedded systems
• Used to control specific hardware components like device drivers
• Allows precise control over processor instructions
• Programs can be very efficient

High-Level Languages

• Statements are closer to human language and mathematics making it easy to learn
• Use data structures such as arrays and records
• Must be translated into machine code to run
• A single statement translates into several machine code instructions
• Translation is done by a compiler or an interpreter
• Compilers translate an entire program into machine code before execution
• Interpreters discover errors as they encounter them

Machine Independence

• High-level programs can run on different processors with minor changes
• A different compiler or interpreter translates the source code for each processor

High-Level Advantages

• Easier to learn
• Supports functions like iterations
• Has libraries of functions that can be imported
• Programs can be written faster
• Easier to understand and debug

Low-Level Advantages

• Programmers have direct control over program operation
• Programs run very quickly
• Code requires less RAM
• Statements control and manipulate specific hardware components Programs such as device drivers are written in assembly code

Compiler

• Translates high-level language into machine code
• Machine code produced can be saved and run when needed

Interpreter

• Translates high-level language into machine code
• No object code is produced
• Translates and executes each line of code immediately
• Stops and displays an error message upon encountering a syntax error

Assembler

• Assembly code needs to be translated into machine code first
• Translates assembly code to machine code

Comparison

• Input: Interpreter and Compiler = High-level language, Assembler = Assembly language.
• Output: Interpreter = No output - program runs straight away, Compiler and Assembler = Machine code.
• How it works: Interpreter = Translates source code and immediately run it, Compiler = Compile source code so it can be run later, Assembler = Assemble source code so it can be run later.
• Speed of execution: Interpreter = Slow as needs to be translated each time it is run, Compiler and Assembler = Fast as it just runs the machine code.
• What end users need to run program: Interpreter = Each end user needs the interpreter and the program, Compiler and Assembler = Users need just the compiled program
• Source code: Interpreter and Compiler = End user can see the source code, Assembler = End user can't see the source code

Explores machine code's binary instructions and limitations. Highlights assembly language as a more accessible, processor-specific alternative. Discusses the translation process via assemblers and the direct correspondence between assembly and machine code.