Calculadora basica de hexadecimal a octal (Assembly DOSBOX TASM)

A calculator must be developed in assembly language, it must work in 16 bits of hexadecimal input, that is, the maximum to be calculated must be in 16 bits, it must be included from the keyboard, the output must be in 15 bits in octal. Must be able to do the 4 basic operations: Addition, Subtraction, Multiplication and Division. It should not be possible to include fractional numbers example 12.25. Negative numbers are allowed and the result can also be negative numbers. All 16 bits must be included, you must not accept less than those bits in the input. The output must be 15 bits (octal). Must be compiled and run on TASM or MASM only, DOSBOX can be used. The Program must indicate (validate) if a result greater than 15 bits is given or if a data greater than that indicated is entered.