new PowerPC instructions for accelerating wasm load/store

[programmerjake]

I'm working on an initial draft design for some new PowerPC instructions that handles wasm memory32/64 load/store with hardware-level address range checking and base address addition: https://bugs.libre-soc.org/show_bug.cgi?id=585

comments/questions/contributions welcome!

[aardappel]

Very cool! See here for the bounds-checking semantics we ended up deciding on: https://github.com/WebAssembly/memory64/issues/3 You'll want to make sure your instructions match that behavior.