Most x86_64 and "Modern" ARM processors are actually a much more 80's-esque RISC processor with parallel instructions, pipelines, etc. The actual hardware binar

Most x86_64 and "Modern" ARM processors are actually a much more 80's-esque RISC processor with parallel instructions, pipelines, etc. The actual hardware binary assembly is actually a high level language the decoder/scheduler makes sense of. Likely they developed a very fast, very efficient core dye. And just swapped decoders at the last minute. Its not much of a stretch that they'd develop the ARM set in parallel b/c of the high risk associated to doing anything with x86.