Matric No - 120805039
Department - Computer Science
CLASSIFICATION OF INSTRUCTION SET ARCHITETURE.
This is the part of the processor that can be seen by the programmer. It is classified into 4 categories;
1) C.I.S.C - Complex Instruction Set Computing
This is the designation of computers with a full set of computer instructions that can execute more than one low-level operation. Due to the discovery of R.I.S.C, C.I.S.C is considered “complex” because of the simplicity of the instructions in R.I.S.C .
In this form of architecture, instructions are highly encoded in order to enhance the code density.Due to the way the instructions are packed together, results are in smaller program sizes, and they have slow memory access.
2) R.I.S.C - Reduced Instruction Set Computing This is the designation of computers that perform lesser number of types of instructions so as to get higher performance and speed. For each instruction type that a computer performs, it needs additional transistors. So many instructions can make the computer slower to give results.
The concept of R.I.S.C was originated by John Cocke in 1974 on IBM 801.It became so popular that Sun microsystems used it to create SPARC microprocessors and also led to the founding of MIPS technologies.
The R.I.S.C makes it easier for programmers to develop codes with smaller instruction sets .Also, new microprocessors can be developed more quickly.
3) M.I.S.C – Minimal Instruction Set Computing
This is the design of computers with a small number of basic operations and there corresponding codes (Opcodes). They are commonly stack based instead of register based with the cause of reducing the size of Opcode specifiers. This kind of architecture is simpler because all instructions operate on the top-most stack entries. Therefore, It gives us a smaller instruction set, a smaller decode unit, and faster execution of single