62USR (user)Calls out and executes in BASIC the machine language program.Format:USR «address> , character variable> , character variable) : numerical data or 4-digit hexadecimal numberAbbreviated form:U.Explanation:• Calls out and executes the machine language program during BASIC programexecution. This is the same as the branch command and CALL to themachine language subroutine. Consequently, when there is a return command in amachine language program, control moves to the next statement following theexecuted statement.• At the point in time when the machine language program is called out, the valuefollowing the character variable> is set in the register.DE register: heading address of memory area of character variable>B register: length of character variable>IX register: address if error-processing routine is announced• At the point in time of return from the machine language program, the value of thedata indicated by the subsequent register becomes the charactervariable>.DE register: heading address of memory area of character variable>B register: length of character variable>• If error-processing is necessary in a machine language program, the followingprocess occurs.(1) An error-processing routine is established by the ON ERROR GOTOstatement in the BASIC program.(2) An error code is substituted in the A register, and is jumped to the addressindicated by the IX register. |
