They’re mostly a superset, but also some instructions were dropped like the bcd opcodes. https://en.m.wikipedia.org/wiki/Intel_BCD_opcodes https://en.m.wikiped

They’re mostly a superset, but also some instructions were dropped like the bcd opcodes. https://en.m.wikipedia.org/wiki/Intel_BCD_opcodes https://en.m.wikipedia.org/wiki/Intel_BCD_opcodes