PTX is on the GPU side and is already supported on available models. On the CPU side, it must be some form of an Arm ISA extension, I believe, like NEON-FHM or SVE-AES… I'm just not sure what the scope of those extensions would be and how they will coexist with ARM’s other extensions.
PTX instructions, and compiler intrinsics, depending on which level of abstraction you’re targeting.