I started programming twenty year ago coding in machine codes for Intel 8080. This microprocessor was my lucky pass to the fascinating world of bits and bytes. Years later developing various emulators of i8080 and tackling with undocumented and partially documented features of this processor I decided to collect real chips from different manufacturers and examine them using the 8080 CPU Exerciser.
At the moment I have 20 processors (from Intel, AMD, National Semiconductor, NEC, Samsung, Texas Instruments, and also manufactured in the Soviet Union and Czechoslovakia). Amongst chips having a year on the label the earliest is dated back to 1974 and the latest is 1980. All CPUs except one are fully functional. I tested them on my Радио-86РК.
Testing revealed that all processors are identical according to the CPU Exerciser except clones from AMD. The AMD processors, AM8080 and AM9080A, behave differently performing the bitwise AND operation (ANA and ANI instruction). The original Intel CPUs and non-AMD clones set the AC (half-carry) flag to the value of the 3rd bit (A3) from the bitwise OR between the accumulator and the argument of ANA or ANI. The AMD clones always zero the AC flag in the ANA and ANI instructions. I don’t know why the original Intel CPU calculates the AC flag in such a weird way.
The double click on the pictures flips the top and the bottom views.
Interestingly, AMD i8080-compatible chips were reverse-engineered from schematics literally stolen from Intel. So, the Intel vs AMD war began from 8080.
This chip is faulty.
This is how I took pictures of all these chips in a quite technological way using one iPhone and two Raspberry Pi:
I hope the collection will grow. I still have only one chip in white ceramic packaging (KR580VM80). If you know i8080 clones from other manufacturers, which are not listed here, I’d appreciate if you let me know.
If you would like to donate any i8080 chip I’ll be happy putting a reference to you next to the image of the chip.