Difference between RISC and CISC

Last updated on November 17th, 2018

The construction of the Central Processing Unit (CPU) functions the aptitude to operate from “Instruction Set Architecture” to which it was invented. The architectural design of the CPU is Reduced instructions set computer (RISC) and Complex instructions set computer (CISC). CISC has the capability of performing multi-step operations or addressing modes within one instruction set. It’s in the Central Processing Unit design to which one instruction employs numerous low-level acts.

RISC is a reduced command set computer which only uses simple instructions that can be split into numerous commands which achieve low-level function within a single CLK cycle, as its name proposes “Reduced Instruction Set”.

CISC stands for ‘’Complex Instruction Set Computer’’. This is a design plan the CPU structured on single commands that are capable in the execution of multi-step operations.

The difference between RISC and CISC Architecture:

RISC stands for Reduced Instruction Set Computer while CISC represents the Complex Instruction Set of a Computer RISC processors have simple commands of about one clock cycle and have an arithmetic mean clock cycle per instruction (CPI) of 1.5 on the other hand a CSIC processor has complex commands that utilizes numerous clocks for execution thus increasing arithmetic mean clock cycle per instruction to a range of 2 and 15.. Thirdly, in RISC Performance is enhanced with more emphasis on software while Performance on CSIC is focused on hardware. There are no memory unit in RISC and thus uses separate hardware to execute an instruction, this is not the case for CISC which utilizes a memory unit to implement a dance instruction. The fifth difference is that a CISC’s have a microprogramming unit while RISC uses a wired unit.

The instruction sets in RISC are reduced and most of these instructions are primitive as opposed to CSIC where the site has a range of different instructions that are utilized for intense operations The instruction set has a variety of different instructions that can be utilized for complex operations CISC has diverse addressing methods and may be utilized to embody a higher-level programming languages easily. Complex addressing methods are utilized using the RISC while CISC readily supports complex addressing methods

Numerous register arrays are present in RISC as opposed to CISC which only has a single register array. RISC processors are vastly pipelined while CISC is not usually pipelined. The complexity of CISC rests in the microprogram while the complexity of RISC rests with the compiler that executes a program

Code expansion in RISC is problematic while this is not the same in CISC. In the decoding of commands CISC is complicated, thus longer execution times as opposed to RISC deciding which is simple thus less time.

CISC architecture is utilized in low-end appliances such as home computerization, security systems while RISC is utilized in high-end appliances such as broadcasting, video and image rendering.RISC does not use external memory during calculations while in CISC external memory is necessary for calculations.

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