Function  4Dh   Get Return Code of a Subprocess (WAIT) 
		Gets return code from functions 31h and 4Dh  (ERRORLEVEL) 
entry   AH      4Dh 
return  AL      exit code of subprogram (functions 31h or 4Ch) 
	AH      circumstance which caused termination 
		00h     normal termination 
		01h     control-break 
		02h     critical device error 
		03h     terminate and stay resident (function 31h) 
note    The exit code is only returned once