Assembly Language
- The first languages were actually direct machine language, where programmers had to program it with direct binary numbers of 1’s and 0’s. It was quite clear to see that this method was incredibly difficult to program, which allowed the introduction of Assembly languages
- Programmers who use assembly language do so for the following reasons:
- Need to make use of specific hardware or parts of the hardware
- To complete specific machine dependent instructions
- To ensure that too much space is not taken up in RAM
- To ensure code can completed much faster
- Assembly languages allow programmers to program with mnemonics. e.g.
- LDA Load - this will ensure a value is added to the accumulator
- ADD Addition - this will add the value input or loaded from memory to the value in the accumulator
- STO, Store - stores the value in the accumulator in RAM
- This is used rather than binary code which allowed continuation of working directly with the hardware but removed an element of complexity
- A mnemonic is received by the computer and it is looked up within a specific table
- An assembler is needed here to check the word so that it can be converted into machine code
- If a match from the word is found e.g. STO the word is replaced with the relevant binary code to match that sequence
Exam Tip
- A question will focus more directly on how the assembler converts to work with the hardware. You must focus on mnemonics being converted from a table and into the corresponding binary code
