RISC vs. CISC Instruction Set Architectures

You are designing a processor for a low-power, real-time embedded system. Which ISA (RISC or CISC) would you choose, and why?

• CISC, because it simplifies compiler design.

• RISC, because it reduces the number of instructions per program.

• RISC, because it uses pipelining for better performance and lower power consumption.

• CISC, because it has complex instructions that can perform multiple operations.

A mobile game requires quick and efficient execution of simple operations repeatedly. Which architecture is more suitable for this use case, and how does it handle memory access?

• CISC, which performs multiple memory operations in one instruction.

• RISC, where memory access is restricted to load/store instructions.

• RISC, where memory is directly accessed during each instruction.

• CISC, where memory is accessed only after all registers are filled.

You notice that a program written for a processor takes more memory space but executes faster. Which type of architecture is the processor likely using, and why?

• RISC, because its simpler instructions allow faster execution but require more lines of code.

• RISC, because it uses fewer instructions but at a slower speed.

• CISC, because it executes faster by breaking tasks into microcode.

• CISC, because its complex instructions reduce memory size while improving execution speed.

A compiler is struggling to optimize instruction sequences for a certain processor, resulting in inefficient code execution. What architecture does this processor most likely follow?

• CISC, as its reliance on backward compatibility affects compiler performance.

• RISC, as it relies heavily on compiler optimization.

• RISC, because it doesn't use microcode.

• CISC, as its microcode hinders compiler efficiency.

A modern CPU uses variable-length instructions but internally breaks down complex instructions into smaller steps for execution. What hybrid approach is this CPU most likely utilizing?

• RISC principles with CISC-level compatibility.

• A purely RISC pipeline.

• CISC architecture with RISC-inspired optimizations.

• An exclusively CISC-based microprocessor.

Why might a processor with fixed instruction lengths perform better in parallel computing tasks?

• It simplifies decoding and pipelining.

• It allows for backward compatibility.

• It supports microcode optimizations.

• It reduces program size.

A device needs to run legacy software while introducing modern optimizations. Which architecture is it likely to use?

• Pure RISC.

• Pure CISC.

• Neither RISC nor CISC.

• A hybrid architecture that integrates CISC backward compatibility and RISC optimizations.

A software engineer must write assembly code for a CPU. They prefer high-level instructions that simplify their task. Which architecture should they choose?

• RISC, because it supports uniform instruction length.

• RISC, because its instructions are simpler.

• CISC, because its complex instructions reduce the number of lines of code.

• CISC, because it prioritizes compiler optimizations.

You are working on a high-performance computing application requiring frequent data transfers between registers and memory. Why might RISC architecture not be ideal?

• RISC's reliance on variable-length instructions adds complexity.

• RISC restricts memory access to load/store instructions, increasing overhead for frequent transfers.

• RISC's compatibility with legacy systems limits performance.

• RISC uses complex instructions that slow down data transfer.

An IoT device needs to run on battery for extended periods while performing simple tasks. Why is RISC the better choice for this application?

• It reduces power consumption due to its smaller instruction set and simplicity.

• It prioritizes microcode for efficient execution.

• It uses complex instructions, reducing the number of operations required.

• It minimizes compiler dependency to save power.