Testing for undocumented opcode / calling Super386 SCALL safely

[ACP]

Below is example code of how to call undocumented opcode. This technique has been used to detect if system CPU is very rare C&T Super386. While it is is FASM syntax porting it to any other assembler shloudn't be a problem as I'm not using any special FASM only features.
https://corexor.wordpress.com/2015/12/05/calling-ct-scall-safely/
Have fun!

[dedndave]

386 ?
that's SO last week

[ACP]

Just like DOS and 16-bit code  ;) Anyway if you take a look at this CPU description it offers something similar to SMM mode but in same ways it is more advance than SMM and I guess most people heard about it just few weeks ago...