In the preceding section, we saw a different kind of machine language. However, this kind of machine language is quite unrealistic for several reasons:
- It addresses memory word by word. This was common in the early days of computer technology, until around 1970. Then, it became more and more common to have processors that address single bytes of memory. Today, probably every processor in production can address single bytes of memory.
- It has instructions of the same length. There has probably never been a machine language where all the instructions are of the same length. A very simple instruction, such as a No-Operation (NOP), can stay in a single byte, while there are processors that have instructions spanning many bytes.
- Any kind of operation operates on a 16-bit word for real-world processors, for any kind of operation—for example, addition. There can be an instruction that operates on single bytes, adding an 8-bit byte to another...