Hacker News Reader

Comment by silverpikezero | Hacker News Reader

The claim about RISC being a No is bizarre. RISC has definitely won, for 2 big reasons: 1. Intel redesigned their x86 processors to execute using a RISC model internally. AMD is using the same idea. A processor architecture is defined by its execution model (not it's external encoding). 2. ARM is more ubiquitous than Intel, and ARM is a RISC architecture. In fact, ARM may be the dominant processor architecture in the next 10 years.

RISC is resoundingly a Yes.

View on HN

The author addresses this:

> It’s possible to nitpick RISC being a no by saying that modern processors translate x86 ops into RISC micro-ops internally, but if you listened to talk at the time, people thought that having a external RISC ISA would be so much lower overhead that RISC would win, which has clearly not happened. Moreover, modern chips also do micro-op fusion in order to fuse operations into decidedly un-RISC-y operations.

The success criteria is not mentioned at all, so there is no clear way of settling this.

yes the brand "risc" failed, but does that mean the idea behind risc presented by the computer science community failed?

I'm no processor expert, but it sounds like to me the paradigm behind risc is both theoretical and practically sound and is a key component in most modern CPU's.

I would disagree. Intel adds more and more special instructions for niche uses (crypto,HPC,virtualization,etc) for the sake of efficiency. This becomes increasingly necessary for performance improvements, because frequency scaling hit its boundary for now and manycore is about to (see Dark Silicon).

One point of RISC was better production yield due to higher die regularity. By this criterion RISC clearly won, and this is also one of the driving factors to CISC-as-microcoded-RISC approach.

> A processor architecture is defined by its execution model (not it's external encoding).

Not quite... how these terms are actually used in computer engineering and computer architecture:

"microarchitecture": How the implementation of a given architecture looks like under the hood.

"instruction set architecture", the externally visible characteristics of the processor from software POV.

"Architecture" and "CPU architecture" usually mean ISA.

"Processor architecture" is not a widely used term, but the first several hits on google refer to the "instruction set architecture" meaning.

AVR, PIC, NEC and alike are classic RISC CPUs and they are already dominant, by a huge margin.

> In fact, ARM may be the dominant processor architecture in the next 10 years.

Are you claiming it isn't dominant now? What kind of chip is in all those set-top boxes people use these days? How about mice?

Set-top box is predominantly MIPS with very few percentage of ARM.

Reply on news.ycombinator.com