10. Low level language concepts

There is a separate mini-website covering assembly language, but here are some key points.

A low level language is one whose programming statements are geared towards a particular CPU family, such as the Intel x86 family of processors. Low level languages are almost (but not quite) machine code.

'Assembly language' is an example of a low level programming language.

Chip makers such as Intel and ARM provide programmers with an Assembly Language with which to code their particular CPU.

Some features of Low Level languages include

• They are CPU specific, making direct use of internal registers
• 'Mnemonics' are used as programming code such as MOV or ADD
• Many different memory modes can be used
• Labels are used as reference points to allow the code to jump from one part to another.

Pros.

• Low level languages are excellent for close control of the CPU, for example many device drivers are coded in assembly language.
• They can be very efficient. Well optimised code written in a low level language can be made to run very quickly compared to code written in a high level language.

Cons

• They are difficult to use as the programming commands can be quite obscure
• A good assembly language programmer needs to know a lot of detail about the internal structure of the CPU - e.g.its registers and memory management methods
• Low level languages produce the least portable source code.

Assembly language looks like this: