[BillBohan]

For the rest of the article start by reading https://en.wikipedia.org/wiki/Datapoint_2200 Datapoint allowed Intel to continue development with the same architecture but required all future processors to have a shuffled instruction set. The mov group on the 8008 and the 2200 was octal 3ds with d being the destination register and s being the source register. The first digit 3 got shuffled to 1. The registers were also shuffled:

8008 bits 8080

A 000 B

B 001 C

C 010 D

D 011 E

E 100 H

H 101 L

L 110 (HL)

(HL) 111 A

Datapoint did not want Intel's future processors to be able to execute Datapoint machine code. They had a lot invested in their software.

Datapoint also had a 5500 processor which was more powerful than the 2200. It was microprogrammed rather than the simpler logic decode of the 2200. It was compatible with the 2200 but had many more instructions (think Z80). Yes it was that instruction set. The engineers at Intel who worked on the 5500 design left to form Zilog.

I worked as an electronics technician at Datapoint and performed test and repair of many 2200 and 5500 processor boards including writing short machine code routines to exercise the hardware.

After I left Datapoint (1977) I worked for Tandy where I repaired thousands of TRS-80 Model 1 computer boards which used the Z80. When the Tandy engineers came into the repair area with the programmers who had written Level 2 BASIC for the TRS-80 with the first masked ROMs, they tried the ROMs on a board and it didn't work. I told them that all the boards in the area needed repair but I had one that I had just repaired. I was introduced to Bill Gates and Paul Allen and the ROMs were put on my repaired board. I typed in a one line program to count and print numbers on the screen and it worked. Bill Gates offered me a job at Microsoft which had about a dozen employees but I turned him down and stayed at Tandy. I wrote more test programs and transitioned into full-time programming.