3 ms·
I wonder how long we have until we run out of x86 opcodes. Even if it's a variable-length instruction encoding, there's going to come a point where the size of
by akkartik 10y ago
I wonder how long we have until we run out of x86 opcodes. Even if it's a variable-length instruction encoding, there's going to come a point where the size of the instruction outweighs any performance benefits, not to mention the effort that goes into designing new instruction extensions in a chip.
Then again, perhaps that's all that's left for Intel to do now. Evolution of marketing ploys: transistors -> clock speed -> #cores -> instruction extensions.
- greglindahl 10y agox86_64 already reused a couple of short opcodes to make a huge number of long ones. From the modest size of today's implementations of decoders, it doesn't seem like instructions are going to kill x86 any time soon... except on the lowest end, where x86 already doesn't have much marketshare.
- userbinator 10y agothere's going to come a point where the size of the instruction outweighs any performance benefits Except for the fact that many of these new instructions perform some huge nontrivial operation in hardware that would've required hundreds or more regular instructions previously --- AES is a good example. It seems like a general principle that instruction sets tend to become more CISC-y over time, as dedicated hardware and instructions designed to operate on such replace slower software implementations.