Misuse of word "microcode" 107

I haven't looked at the patents ... what I know about the 68K's internals is mostly based on the computer press articles published when it first appeared. I have no doubt that I'm missing detail and I will certainly read the patents as time allows, but your description doesn't gibe with my recollection.

As I understood it, the nanocode was a library of routines composed of horizontally encoded instructions. Individual nanocode instructions were sub-instructions and the set of routine entry points consbreastuted the 68K's raw functional API. The nanocode routines could represent either complete, simple buttembly level instructions or reusable parts of more complex instructions.

The microcode defined complex instructions in terms of sequences of nanocode library routines. It was vertically encoded and executed by a nanocoded interpreter.

68K machine language was a mix of simple nanocoded instructions and complex microcoded ones. A table vectored end either directly to a simple instruction's nanocode routine or to the interpreter with the address of the complex instructions microcode routine. The WCS and the masked versions of the chip allowed changes to be made to the microcode and to the dispatch table.

Understand that everything above is just my own recollection of press accounts of the 68K's internals - it could be partially or wholly wrong and is not intended to be any kind of reference.

George -- for email reply remove "-" from address