INTRODUCTION
Reduced instruction set computing, or RISC, is a CPU design strategy based on the insight that simplified instruction set (as opposed to a complex set) provides higher performance when combined with a microprocessor architecture capable of executing those instructions using fewer microprocessor cycles per instruction. A computer based on this strategy is a reduced instruction set computer, also called RISC. The opposing architecture is called complex instruction set computing, i.e. CISC.
Various suggestions have been made regarding a precise definition of RISC, but the general concept is that of a system that uses a small, highly optimized set of instructions, rather than a more specialized set of instructions often found in other types of architectures. Another common trait is that RISC systems use the load/store architecture, where memory is normally accessed only through specific instructions, rather than accessed as part of other instructions like add.
Well-known RISC families include DEC Alpha, AMD 29k, ARC, ARM, Atmel AVR, Blackfin, Intel i860 and i960, MIPS, Motorola 88000, PA-RISC, Power (including PowerPC), SuperH, and SPARC. In the 21st century, the use of ARM architecture processors in smart phones and tablet computers such as the iPad, Android, and Windows RT tablets provided a wide user base for RISC-based systems. RISC processors are also used in supercomputers such as the K computer, the fastest on the TOP500 list in 2011, second at the 2012 list, and fourth at the 2013 list, and Sequoia, the fastest in 2012 and third in the 2013 list.
ARCHITECTURE
The RISC was characterized by 8-Bit architecture having 8-bit Registers, ALU, RAM, Decoders, Counters, Display Unit and Control Unit. The instruction set consists of 15 primitive instructions that were encoded using 16-Bit encoding. The RISC is designed using the Hardware Descriptive Language viz. Verilog HDL. Machine instructions were implemented