[kens]

The NEC V33 (1988) was a hardwired (not microcoded) version of the 286. The decision not to use microcode might be related to the long lawsuit between Intel and NEC over microcode.

Also, as krylon points out, RISC chips generally don't use microcode.

[dfawcus]

According to the datasheet, which I've just looked at, it was not a '286 equivalent. Rather it added a paging mechanism whereby a 20 bit 'linear' address was mapped to a 24 bit 'physical' address. Using 1024 16k pages, so a bit like an internal LIM 4.0 scheme, but limited to 16M total rather than 24M.

It has a pair of new instructions, to enter and exit the extended mapping mode, and the mappings are only changeable when not in the extended mapping mode. So a form of memory protection.

See pages 20 and 21 of the following:

https://datasheet.datasheetarchive.com/originals/scans/Scans...

[kens]

You are correct.

[MichaelZuo]

Thanks Ken, that's pretty fascinating info. It makes me wonder if, with modern design software, a modern 64 bit CPU could be made without any microcode either.

[monocasa]

Depending on what you mean by modern, there are RISC-V cores that don't use microcode, including 64-bit OoOE cores like SonicBOOM and the T-Head C920.