Chapter 19 Processor and Computer Architecture Flashcards
What is a hard wired control unit?
A control unit constructed as a logic circuit, with all machine-code instructions handled by hardware. Used for RISC.
What is a microprogrammed control unit?
When the control unit has a ROM component in which the microcode for microprogramming is stored (firmware). Used for CISC.
Compare the instructions of RISC and CISC.
RISC has fewer and simpler instructions with less instruction formats while CISC has more and more complex instructions with many instruction formats. RISC has fixed-length instructions while CISC has multi-cycle instructions.
Compare the addressing modes of RISC and CISC.
RISC has fewer addressing modes while CISC has more addressing modes.
Compare how many registers RISC and CISC use.
RISC has many register sets while CISC has few register sets.
Compare the ease of pipelining between RISC and CISC.
It’s easier to pipeline with RISC.
What is pipelining?
A form a instruction-level parallelism where multiple instructions are overlapped during execution.
Describe SISD.
A single instruction with a single data stream. Found in early PCs.
Describe SIMD.
A single instruction with multiple data streams. It’s how vector processors work.
Describe MIMD.
Multiple instructions with multiple data streams. Used in modern computers.
Describe MISD.
Multiple instructions with a single data stream. Not often used in computers.
Describe massively parallel computers.
When a large group of computers work together on a network infrastructure to make complex calculations.
