CPU Shack: Intel D8089-3 I/O Processors - 3 Left

[CPUShack]

The Intel 8089 I/O Processor is an interesting beast, and I do mean a beast.

I use to think of these as a support chip for the 8086, and in a lot of way it is, but it is actually much more powerful then that.

Even in 1986 the 8089 sold for $60 while the 8086 sold for $20, the reason is the 8089 was made in a lot less quantities and actually is a pretty complicated chip.

Internally its a 16'bit CPU, complete with dual sets of registers (20-bits each, with a Program Counter) as well as a full ALU. It has its own I/O based instruction set, 64 different instructions, including all the usual arithmetic. It lacks a stack though so no stack based instruction (plenty of jump instructions but no returns)

It was significant enough that Adam Osborne actually wrote a separate book for it (to go with his Microprocessor guides).

Overall the purpose of the 8089 was to bring mainframe functionality to the 8086, and thats probably part of the high cost

Here is a nice die shot Birdman made
https://commons.wikimedia.org/wiki/File:Intel_8089_die2.JPG

I have a few nice ones of these for your enjoyment

5x Intel D8089-3 $10

[xhoba]

I'll take one, please.

[Twinrocket]

I'll take one, please.

[CPUShack]

3 Left

[Chiefish]

I only have one made by fujitsu , so ill take one please