I'd argue it's more similar to 64-bit x86, and the only difference between the "standard" x86_64 ABI and x32 ABI is that x32's pointers are 32bit. Everything e

I'd argue it's more similar to 64-bit x86, and the only difference between the "standard" x86_64 ABI and x32 ABI is that x32's pointers are 32bit. Everything else matches the 64-bit version - not the 32bit one - the instruction encoding, the extra registers, the minimum isa extensions (x86_64 puts a baseline of sse2), the calling convention advantages etc. etc.