Summary

	In this topic, the instructions fetch and execute cycles are described.
	Assembly programs can be written using different instruction types such as: three-address instructions,
	two-address instructions, one-address instructions and zero-address instructions.
	Addressing modes specify where the instruction operands are located.
	Addressing modes explained in this topic are immediate, direct, indirect, relative, displacement and stack.
	Instruction types can be classified according to their functionality.
	A comparison between fixed-length instructions and variable-length instructions is given.