1.1.2 CISC and RISC

what is CISC

complex instruction set computer

what is RISC

reduced instruction set computer

compare the power comsumption and cost of RISC and CISC

CISC more power consumptions and more expensive because of complex circuitry, RISC less power consumption and less expensive due to more simplistic circuitry.

benefits of CISC

compatable with dated software, less RAM required to load CISC programs (has more modes of addressing, shorter assembly code length)

drawbacks of RISC

harder to code complex code (limited instruction set), longer programs ( may take up more storage), CPUs run at a lower clock speed

which allows pipelining

RISC only takes one clock cycle to complete it also has a limited instruction set and which allows for efficient execution of instructions in parallel.

compare the complexity of the source code

RISC has more complex source code than CISC, it has to use more instructions so it becomes more complex.

uses of CISC

laptops, desktops

uses of RISC

mobile phones, tablets

benefits of RISC

pipelining is possible because instructions usually take 1 clock cycle to complete, less circuitry easier and cheaper to manufacture. low power consumption

drawback of CISC

chips are larger and more complex, more power consumption, more expensive to manufacture, heat emission are high.

How are today’s processors built

Combination of CISC and RISC in order to maximise the advantages of both.

Drawback of a today’s desktop computers and mini computers

increases design complexity and cost due to the integration of both CISC and RISC ISA(instruction set architecture). Produces more heat.