My first thought was to use the Address calculation logic for an additional ALU, then... my second thought was trying to justify this during a code review... an

My first thought was to use the Address calculation logic for an additional ALU, then... my second thought was trying to justify this during a code review... and lastly, why Microsoft used the LDT upper byte to make Xenix 286 incompatible... and the headache that changing architectures made for poor programming.