[OsrsNeedsf2P]

Right, but the program is generated by the miner. So the miner could just generate a program that has no branching, and run it on a GPU.

[tardedmeme]

Each program is guaranteed to have a certain number of certain types of instructions, such as (IIRC) exactly one divide instruction.

[hyc_symas]

Since the programs are randomly generated, there's no guarantee that any particular program always uses some number of any particular instruction. There's only a probability, X/256 instructions will be somesuch operation.