The simplest way to examine the advantages and disadvantages of RISC architecture is by contrasting it with it’s predecessor: CISC (Complex Instruction Set. RISC and CISC Architectures – Difference, Advantages and . Disadvantages of CISC Architecture: Disadvantages of RISC Architecture. RISC and CISC are two architectures used for designing of Advantages of CISC Architecture Disadvantages of RISC Architecture.

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Every processor is built with the ability to execute a set of instructions for performing a limited set It has a limited number of addressing modes, typically 3 to 5. It uses disc and highly optimized set of instructions which are generally register to register operations. The major characteristics of CISC architecture are It has a large number of instructions, typically from to instructions.

This makes to place extra functions like floating point arithmetic units or memory management units on the same chip. Instructions are in the form — Opcode operational code and Operand. Notify me of new comments via email.

The instruction set is embedded in the hardware which serves as a bridge between software and hardware.

RISC and CISC Architectures – Difference, Advantages and Disadvantages – Electronic Pull

The operand is a memory register where instruction applied. As each instruction became more accomplished, fewer instructions could be used to implement a given task. This mirco program consists of a sequence of microinstructions.

Small code sizes, high cycles per second. It closely resembles a command in a higher level language.


RISC functions use disadvantahes a few parameters, and the RISC processors cannot use the call instructions, and therefore, use a fixed length instruction which is easy to pipeline. You are commenting using your Facebook account. If number of complex instructions within the instruction set of processor is increased, the processor working is slow down due to more complex decoding of instructions and time consuming.

The speed of the operation can be maximized and the execution time can cizc minimized. Their aim is to share their knowledge about Electronics on this blog.

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Thus, the “MULT” command described above could be divided into three separate commands: They provide a high level of abstraction, conciseness and power. These cycles fetch, decode and execute of one or more instructions are overlapped in this pipeline technique.

Hardware architecture may be implemented to be either hardware specific or software specific, ad according to the application both are used in the required quantity. The above figure shows the architecture of CISC with microprogrammed control and cache memory. The processor spends much time waiting for first instruction result before it proceeds with next subsequent instruction, when a compiler makes a poor job of scheduling instruction execution. It supports complex addressing modes.

Depending upon the type of instruction applied, addressing modes are of various types such as direct mode where straight data is accessed or indirect mode where the location of the data is accessed.

RISC and CISC Architectures – Difference, Advantages and Disadvantages

Processors disadvantates identical ISA may be very different in organization. Low cycles per second, large code sizes. Very less number of instructional formats, a few numbers of instructions and a few addressing modes are needed.


Transistors used for storing complex instructions. And all three are affected by the instruction set architecture. Let’s say we want to find the product of two numbers – one stored in location 2: Most RISC processors use hardwired control for the machine instruction and hence no need for microinstructions thereby it is not necessary to access a microprogram control memory during instruction execution as in case of CISC processor.

CISC – Advantages and disadvantages table in A Level and IB Computing

It is performed by overlapping the execution of several instructions in a pipeline fashion. With an objective of improving efficiency of software development, several powerful programming language s have come up, viz. To find out more, including how to control cookies, see here: Multiplying Two Numbers in Memory On the right is a diagram representing the storage scheme for a generic computer. These have many instruction formats and many addressing modes.

So a unique instruction set is employed for each processor, where machine language programs of one processor will not run on different processor. Instruction Count of the CPU.