question: public String isValidOperand ( FullArgument operand , boolean executeNow ) { if ( operand . address . type == Op . ERROR ) { return "Invalid Expression" ; } if ( ( operand . address . type & Op . MEM ) != 0 ) { return isValidAddress ( operand . arg , operand . address . size , executeNow ) ; } return null ; }
target:  Checks whether an operand is valid