Q38317: CodeView Gives "Illegal Instruction" on Clone 386

Article: Q38317
Product(s): See article
Version(s): 2.20
Operating System(s): MS-DOS
Keyword(s): ENDUSER | CV | mspl13_basic
Last Modified: 23-NOV-1988

Some clones that are not entirely IBM-compatible under CodeView may
give an "illegal instruction" message upon executing Go (F5), and then
hang, requiring a warm boot. If the instruction being called illegal
is FINIT or FNINIT, the particular ROM BIOS probably has a built-in
387 emulator. Either turn off the emulator, or set the environment
variable SET NO87=(some string).