The Intel 80188 is a version of the Intel 80186 microprocessor with an 8 bit external data bus, instead of 16 bit. This makes it less expensive to connect to peripherals. The 80188 is otherwise very similar to the 80186. It has a throughput of 1 million instructions per second.
As the 8086, the 80188 featured four 16-bit general registers, which could also be accessed as eight 8-bit registers. It also included six more 16-bit registers, which included, for example, the stack pointer, the instruction pointer, index registers, or a status word register that acted like a flag, for example, in comparison operations.
Just like the 8086, the processor also included four 16-bit segment registers that enabled the addressing of more than 64 KB of memory, which is the limit of a 16-bit architecture, by introducing an offset value that was added, after being shifted left 4 bits, to the value of another register. This addressing system provided a total of 1 MB of addressable memory, a value that, at the time, was considered to be very far away from the total memory a computer would ever need.
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