Microprocessors can be classified based on the following criteria:
1. The width of data that can be processed
2. The instruction set Classification of Microprocessors based on the Data Width Depending on the data width, microprocessors can process instructions.
The microprocessors can be classified as follows:
1. 8 – bit microprocessor
2. 16 – bit microprocessor
3. 32 – bit microprocessor
4. 64 – bit microprocessor
Classification of Microprocessors based on Instruction Set:
The size of the instruction set is another important consideration while categorizing microprocessors. Initially, microprocessors had very small instruction sets because complex hardware was expensive as well as difficult to build. As technology had developed to overcome these issues, more and more complex instructions were added to increase the functionality of microprocessors. Let us learn more about the two types of microprocessors based on their instruction sets.
Reduced Instruction Set Computers (RISC):
RISC stands for Reduced Instruction Set Computers. They have a small set of highly optimized instructions. Complex instructions are also implemented using simple instructions, thus reducing the size of the instruction set. Examples of RISC processors are Pentium IV, Intel P6, AMD K6 and K7.
Complex Instruction Set Computers (CISC):
CISC stands for Complex Instruction Set Computers. They support hundreds of instructions. Computers supporting CISC can accomplish a wide variety of tasks, making them ideal for personal computers.
Examples of CISC processors are Intel 386 & 486, Pentium, Pentium II and III, and Motorola 68000.