- Tracing the roots of the 8086 instruction set to the Datapoint 2200 minicomputer (righto.com)
The Intel 8086 processor started the x86 architecture that is still extensively used today. The 8086 has some quirky characteristics: it is little-endian, has a parity flag, and uses explicit I/O instructions instead of just memory-mapped I/O. It has four 16-bit registers that can be split into 8-bit registers, but only one that can be used for memory indexing. Surprisingly, the reason for these characteristics and more is compatibility with a computer dating back before the creation of the microprocessor: the Datapoint 2200, a minicomputer with a processor built out of TTL chips. In this blog post, I’ll look in detail at how the Datapoint 2200 led to the architecture of Intel’s modern processors, step by step through the 8008, 8080, and 8086 processors.
- Intel 4004 (Wikipedia)
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60 (equivalent to $450 in 2023), it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs.