Full Form of RISC:
Reduced Instruction Set Computer
RISC Full Form is Reduced Instruction Set Computer. A kind of microprocessor that takes into use a highly optimized and small instruction set is called RISC or Reduced Instruction Set Computer. It is different from other architecture types since it does not use a more specialized instruction set. The 5 design principles used by the RISC are (1) Single Cycle Execution: The highest possible rate of execution in the majority of the traditional CPU designs is one instruction per basic cycle of the machine. Additionally, there is a lower limit on the cycle time for any given technology. Most instructions generated by the compiler are simple in complex CPUs. The RISC, on the other hand, gives a huge amount of stress on the single cycle execution, even though it results in multiple instruction sequence’s syntheses for operations that are not performed frequently.
(2) Absence of microcode: An interpretive overhead layer is added by the microcode. It results in the rise of the number of cycles executed every second. Hence, the simplest instructions, along with the complex ones, need several cycles to execute. (3) Few modes of addressing and simple instructions: Those addressing modes and instructions that use multi-cycle or microcode instructions are avoided by the RISC.
(4) RR, load, and store design: The memory is accessed by the loads and stores only. All the others perform the RR operations. (5) Deep and Efficient Pipelining: In order to avoid the complexities that arise by horizontal microcode, and at the same time, making the use of hardware parallelism convenient, pipelining is used by the fast CPUs. For supporting pipelining, the tuning of the instruction set must be done carefully.