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Is the 8088 processor 8 bit or 16 bit?

In Randall Hyde's Art of Assembly it says the 8088 CPU was 8 bits whilst the 8086 was 16 bits solely because of the width of the data bus.

I have always thought that the address size determined the size of the CPU.

Please shed some light on this issue.

Solution

  • From Wikipedia

    The 16-bit registers and the one megabyte address range were unchanged, however. In fact, according to the Intel documentation, the 8086 and 8088 have the same execution unit (EU)—only the bus interface unit (BIU) is different.

    So the processor is functionally identical, but the memory bus is smaller. The main purpose was for compatibility with 8-bit interfaces. If a 16-bit interface was wanted, then it would take 2 CPU cycles to accomplish what the 8086 could do in one.

    There was a greater availability of 8-bit chips at the time.