How would you modify the instruction format and add to the instruction set?

Figure 3.1 (a) shows the basic instruction format for a single-address computer.

However, if there are further operations requiring less secondary information, then another instruction format can be provided with a longer operation code field.

A problem in any word-oriented computer with instruction formats shorter than the word is how to address individual instructions.

An example of a three-address instruction format on an early computer is shown in Figure 3.6.

A two-address instruction format is usually still too long.

Basic mode is another whole form of instruction formats and addressing.

Although its instruction format resembled that of the earlier machines, it was not compatible with them.

The instruction formats provide a model for memory and data management.

The basic instruction formats allowed for one, two and three word instructions.