Flashcards
CISC and RISC
Cards in this deck (10)
- 1What are instruction sets?The instructions that a processor can apply to a flow of data during run-time of an application. This gives the capability to push their hardware further and further witch each new generation as there is not a standard instruction set for all processors.
- 2What happens if an instruction is read that doesn't occur in the instruction set?an error flag is produced and the computer halts that program tree.
- 3What is the primary goal of CISC architectureComplex Instruction Set Computer complete a task in as few lines of assembly as possible. This is achieved by building processor hardware that is capable of understanding & executing a series of operations. With CISC, the instruction can do an entire sequence of operations across multiple clock cycles.
- 4What does RISC provide?a fairly small and basic instruction set where in every operation cycle only one value is fetched or stored from/to memory. Only uses simple instructions that can be executed within one clock cycle.
- 5What are the advantages of CISC?Compiler has to do very little work to translate high level statements into assembly.
Length of code is relatively short
Very little RAM is required to store instructions
Emphasis is put on building complex instructions directly into the hardware - 6What are the advantages of RISC?Each instruction requires only one clock cycle to execute, the entire program will execute in the same amount of time as the multi-cycle MULT command
These reduced instructions require less transistors of hardware space than the complex instructions, leaving more room for general purpose registers
All instructions execute in a uniform amount of time
Pipelining is possible - 7What are the key differences between RISC and CISC?RISC has fewer instructions
To do complex tasks, RISC CPUs have to combine simple operations from their reduced instruction set.
RISC can be more efficient at simpler tasks bc the instruction set is less complex - 8In RISC and CISC, how is speed used?RISC CPUs run at a lower speed, able to perform simpler tasks more quickly but worse at more intensive tasks.
- 9How does electricity usage affect both processors?Because CISC CPUs are larger, they use more electricity.
RISC are designed to use less power and can go into sleep mode when not actively processing a program - 10What is the design and cost of both processors?RISC CPUs are much smaller than CISC, therefore more functions can be combined with the CPU in one chip.
CISC CPUs are usually built into a system which has a heat sink and fan to cool them down. Smartphones/ tablets do not have space for these fans.
RISC CPUs cost less to make and use less power
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- A level Computer Science (Unit 1 - Topic 1) Flashcards on CISC and RISC, created by Ariana Parr on 14/02/2022.
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- Ariana Parr
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