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More about CISC and RISC architectures and instruction sets..

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Amine Moulay Ramdane

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Nov 21, 2020, 3:44:12 PM11/21/20
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Hello..


More about CISC and RISC architectures and instruction sets..

Read here:

https://vivadifferences.com/20-difference-between-risc-and-cisc-architecture/

It says the following:

Disadvantages Of RISC:

- Designing compiler using RISC is complicated.

This is what i don't like in RISC instruction set, it pushes the complexity towards the software compilers, also the RISC compilers must implement instruction scheduling algorithms such as to take advantage of parallelism in instruction processing and if this is poorly handled, than the RISC machine's performance will directly be impaired. And x86 instruction set is much richer than RISC instruction set, so i think that it is much more higher level , so i think that it permits a higher level programming that is safer, since i think that the x86 hardware of the x86 instruction set was stabilized and is in my opinion much safer than the RISC approach. This is why i don't like ARM or RISC-V because they push the complexity towards the compiler side and i think that it is less safe than the CISC approach.

Read my following previous thoughts:

What about x86 vs ARM processors ?

x86 instruction set is CISC and x86 architecture is RISC(inside)
and ARM instruction set is RISC and ARM architecture is RISC.

The CISC approach attempts to minimize the number of instructions per program, sacrificing the number of cycles per instruction. RISC does the opposite, reducing the cycles per instruction at the cost of the number of instructions per program.

The RISC ISA emphasizes software over hardware. The RISC instruction set requires one to write more efficient software (e.g., compilers or code) with fewer instructions. CISC ISAs use more transistors in the hardware
to implement more instructions and more complex instructions as well.

CISC simplify the software by needing hardware structure to be more complex.

Programming CISC-based computers is easier than in other designs because there is a single instruction for both simple and complex tasks.

Programming in RISC is more difficult and time-consuming than in the other design, because most of the complex instructions are simulated using simple instructions.

So i think that CISC instruction set is less error prone to program than
RISC instruction set, so i think that x86 instruction set is better
for safety.


Thank you,
Amine Moulay Ramdane.









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