error diagnostic messages with a severity code of integer or higher, appear in the assembler listing. Error diagnostic messages
with a severity code lower than integer do
not appear in the listing, and the severity codes associated with
those messages are not used to set the return code issued by the assembler.
Any severity code from 0 through 255 can be specified. Error diagnostic
messages have a severity code of 0, 2, 4, 8, 12, 16, or 20. MNOTEs
can have a severity code of 0 through 255.