RISC : It means Reduced Instruction Set Computer, it is a computer with fewer instructions with simple constructs, so they can be executed much faster within the CPU without having to use memory as often. This type of computer is classified as a reduced instruction set computer or RISC.
RISC characteristics
1. Relatively few instructions
2. Relatively few addressing modes
3. Memory access limited to load and store instructions
4. All operations done within the registers of the CPU
5. Fixed length, easily decoded instruction format
6. Single cycle instruction execution, relatively large no of registers in the processor unit
7. Hardware rather than micro programmed control
8. RISC systems shorten execution time by reducing the clock cycles per instruction ( that is simple instructions take less time to interrupt)
CISC : It means complex instruction set computer, A computer with large number of instructions is classified as a complex instruction set computer.
Characteristics of CISC
1. A large number of instructions typically from 100 to 250 instructions
2. A large variety of addressing mode typically from 5 to 20 different modes
3. Some instructions that perform specialized tasks and are used frequently
4. Variable length instruction format
5. Instructions that manipulate operands in memory.
6. Includes multi-clock complex instructions Memory-to-memory: "LOAD" and "STORE" incorporated in instructions
7. Usually implemented as micro programmed control to tackle the variable length instructions.
8. CISC systems shorten execution time by reducing the number of instructions per program
RISC characteristics
1. Relatively few instructions
2. Relatively few addressing modes
3. Memory access limited to load and store instructions
4. All operations done within the registers of the CPU
5. Fixed length, easily decoded instruction format
6. Single cycle instruction execution, relatively large no of registers in the processor unit
7. Hardware rather than micro programmed control
8. RISC systems shorten execution time by reducing the clock cycles per instruction ( that is simple instructions take less time to interrupt)
CISC : It means complex instruction set computer, A computer with large number of instructions is classified as a complex instruction set computer.
Characteristics of CISC
1. A large number of instructions typically from 100 to 250 instructions
2. A large variety of addressing mode typically from 5 to 20 different modes
3. Some instructions that perform specialized tasks and are used frequently
4. Variable length instruction format
5. Instructions that manipulate operands in memory.
6. Includes multi-clock complex instructions Memory-to-memory: "LOAD" and "STORE" incorporated in instructions
7. Usually implemented as micro programmed control to tackle the variable length instructions.
8. CISC systems shorten execution time by reducing the number of instructions per program