Unit 8 Program Construction

Assemblers

Assemblers

A program which allows to convert low level language into machine code

Interpreter

Converts each line of the source code into machine code, and execute each line of the code as it run. Which is then executed by the cpu

Compiler

Converts source code into executable machine code

Explain the 4 main stage of compilation

1. Lexical analysis

   • removes unneeded comments and spaces

   • Creates a symbol table which holds the address of variables, labels and subroutines

2. Syntax analysis

   • The spelling and gramma of token are checked

   • If syntax error is found, error message is shown

   • Variable are checked to make sure it has properly declared

3. Code generation

   • Machine code is generated

   • Code is optimised

4. Code optismisation

   • been optismised to be fast, efficient and uses as little of the computer's resources as possible.

What is a translator

It translate a program written in one language to another language without changing the program

What is a syntax error

An error that occurs when the rules of the language have not been adhered to, found during translation.

What is a run time error

An unexpected error that stops the program from executing. E.g. A user inputting a string into a variable that is declared as an integter.

What is a logical error

An Error that doesn't stop a program executing but results in the wrong answer.

What is a linking error

An error that occurs when a program calls a function that is not correctly linked.

What is a rounding error

The difference between the original value and the value it is rounded to.

What is a truncating error

The difference between the original value and the value it is truncated to.