Write the following subroutine, which captures a user$-$entered string at run$-$time, storing it as a null$-$terminated character array $($just like the $.$STRINGZ pseudo$-$op$,$ with the big difference that $.$STRINGZ requires a hard$-$coded character array at compile$-$time$).$ ;$------------------------------------------------------------------------$ ; Subroutine: SUB$\_$GET$\_$STRING ; Parameter $($R$1)$: The starting address of the character array ; Postcondition: The subroutine has prompted the user to input a string, ; terminated by the $[$ENTER$]$ key $($the "sentinel"$),$ and has stored ; the received characters in an array of characters starting at $($R$1).$ ; the array is NULL$-$terminated; the sentinel character is NOT stored. ; Return Value $($R$5)$: The number of non$-$sentinel chars read from the user. ; R$1$ contains the starting address of the array unchanged. ;$-------------------------------------------------------------------------$ This subroutine should prompt the user to enter in a string of text, ending with the $[$ENTER$]$ key. The string of text will be stored starting at whatever address is specified by $($R$1)$ and will be NULL$-$terminated $($i$.$e$.$ the subroutine will store zero $($x$0000=$ #$0=\text{'}\backslash 0\text{'})$ as a sentinel at the end of the array$).$