Patrick Chase (patrickjchase.delete@this.gmail.com) on February 3, 2013 4:29 pm wrote:
> Paul A. Clayton (paaronclayton.delete@this.gmail.com) on February 2, 2013 11:10 am wrote:

> > A clean RISC like Alpha (or--from what I have read--AArch64) would be much more friendly to fast bring-up
> > of a decent microarchitecture. (Classic ARM seems to be somewhere in the middle--not as complex as x86 but
> > not as simple as Alpha--, but even with Thumb2+classic ARM it might be closer to Alpha than to x86.)
>
> AArch64 is indeed a nice, classic RISC architecture. In particular they fixed the biggest
> single limitation of classic ARM (spending instruction encoding bits on condition-based
> predication at the expense of GPRs). I'd put it somewhere between MIPS and Alpha on
> the "architectural purity scale", and that's a pretty good place to be.

What are some aspects of the ISA that make it less clean than Alpha, would you say?