The Mac IIci was the first 32 bit clean machine. Plenty of dynamically typed languages have used the bottom bits in an address to store tags. You have two avai

The Mac IIci was the first 32 bit clean machine. Plenty of dynamically typed languages have used the bottom bits in an address to store tags. You have two available on a 32 bit machine, three on 64 bit. The SPARCv7 has instructions that will do arithmetic on tagged values.