читаю MSDN
[msdn]ASSUME segregister:name [[, segregister:name]]...
ASSUME dataregister:type [[, dataregister:type]]...
ASSUME register:ERROR [[, register:ERROR]]...
ASSUME [register:]] NOTHING [[, register:NOTHING]]...[/msdn]
использую:

__asm
{
...
assume    edx: PMYTYPE
...
}

компилю:

: error C2220: warning treated as error - no object file generated
: warning C4405: 'edx' : identifier is reserved word
: error C2400: inline assembler syntax error in 'opcode'; found 'edx'
NMAKE :  U1077: 'cl' : return code '0x2'

где косяк? в чём прикол?