x86_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

x86_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.