Question

Please answer the following:

a. What are the key design issues for a microprocessor instruction set?

b. Why do you consider the above design issues to be important?

(please type answer)

Answer 1

Key Design Issues For A Microprocessor Instruction Set are

1.CISC (Complex Instruction Set Computer)

2.Reduced Instruction Set Computers (RISC)

1.CISC:- Make assembly language (AL) as much like high-level language (HLL) as possible to reduce the "semantic gap" between AL and HLL

THE CISC DESIGN ISSUSE IS IMPORTANT BECAUSE:-

It reduce compileer complexity and aid assembly language programming - compilers not too good at the time (e.g., they did not allocate registers very efficiently)

reduce the code size - (memory limited at this time)

improve code efficiency - complex sequence of instructions implemented in microcode

2.RISC:-Addresses these problems to improve speed.

General Characteristics of RISC:emphasis on optimizing instruction pipeline

a) one instruction completion per cycle

b) register-to-register operations

c) simple addressing modes

d) simple, fixed-length instruction formats

THE RISC DESIGN ISSUSE IS IMPORTANT BECAUSE:-

limited and simple instruction set and addressing modes

large number of registers or use of compiler technology to optimize register usage

hardwired control unit

RISC Instruction-Set Architecture (ISA) can be effectively pipelined