These were the instructions that were stubbed out when
introducing the decode skeleton.
Backports commit 39eea56172e668cc4cca611ed9166779df54ac63 from qemu
Including only 4, as-yet unimplemented, instruction patterns
so that the whole thing compiles.
Backports commit 38388f7ee3adc04a7e7246c04352451c4f8d00fb from qemu