The Harris company, well known for being an early second source making x86 chips under license, eventually produced a fully static CMOS 80C286 of their own design (later known as the Intersil 80C286 and apparently also sold by Intel). This processor was very popular in late PC AT clones on account of being able to run at a whopping 25 MHz.
Does the Harris 80C286 have any difference in behaviour from an Intel 80286 as far as the programmer is concerned? For example:
- Do any instruction timings differ?
- Are there any additional or different documented or undocumented instructions?
- Does the Harris 80C286 microcode behave different from the Intel 80286 microcode?
- Is it possible for a program to detect that it's running on a Harris 80C286?
Despite its popularity, very little details on the innards of this chip seem to be available on the internet.