shac ron ₪‎ on Nostr: arm64: registers can be addressed as w (32-bit) or x (64-bit). ALU instructions take ...

arm64: registers can be addressed as w (32-bit) or x (64-bit). ALU instructions take either type and do the op of the matching size.
riscv64: registers can only be accessed as 64-bit. We created a set of duplicate ALU instructions that ignore the top bits, discard overflows, and then sign extend the result every time to support 32-bit math.