It takes a heck of a lot longer if you wait until all the advanced features are ready before you publish anything at all.
I think RISC-V did pretty well to get everything in RVA23 -- which is more equivalent to ARMv9.0-A than to ARMv8.0-A -- out after RV64GC aka RVA20 in the 2nd half of 2019.
We don't know how long Arm was cooking up ARMv8 in secret before they announced it in 2011. Was it five years? Was it 10? More? It would not surprise me at all if it was kicked off when AMD demonstrated that Itanium was not going to be the only 64 bit future by starting to talk about AMD64 in 1999, publishing the spec in 2001, and shipping Opteron in April 2003 and Athlon64 five months later.
It's pretty hard to do that with an open and community-developed specification. By which I mean impossible.
I can't even imagine the mess if everyone knew RISC-V was being developed from 2015 but no official spec was published until late 2024.
I am sure it would not have the momentum that it has now.
I think RISC-V did pretty well to get everything in RVA23 -- which is more equivalent to ARMv9.0-A than to ARMv8.0-A -- out after RV64GC aka RVA20 in the 2nd half of 2019.
We don't know how long Arm was cooking up ARMv8 in secret before they announced it in 2011. Was it five years? Was it 10? More? It would not surprise me at all if it was kicked off when AMD demonstrated that Itanium was not going to be the only 64 bit future by starting to talk about AMD64 in 1999, publishing the spec in 2001, and shipping Opteron in April 2003 and Athlon64 five months later.
It's pretty hard to do that with an open and community-developed specification. By which I mean impossible.
I can't even imagine the mess if everyone knew RISC-V was being developed from 2015 but no official spec was published until late 2024.
I am sure it would not have the momentum that it has now.