I wrote: > The 68000 has three separate 16 bit ALUs: one for DataLow, one for > AddressLow and another for AdressHigh. DataHigh can be processed by > either the first or the second one. The first one implements all > operations while the other two only do add/subtract and some limited > shifting. > > See figure 8 of: > https://www.computer.org/csdl/mags/co/1979/02/01658617.pdf
Ooops- my explanation got the last two ALUs backwards. DataHigh and AddressHigh share an ALU. Note that in the conclusion to this 1979 article, the Motorola engineers say "It is a 32-bit architecture that supports many data types and data addresses." - Jecel.
