1. Write a LC-3 subroutine for printing “Hello” for N times. Write a main program to input N from the keyboard, call the subroutine and then output “Hello” for N times.

Here is the LC-3 subroutine for printing "Hello" for N times:

; Subroutine to print "Hello" for N times
; Input: R0 = N
; Output: None

PRINT_HELLO  AND R1, R1, #0          ; Initialize counter to 0
            LD R2, HELLO_MSG        ; Load the address of "Hello" message
LOOP        ADD R1, R1, #1          ; Increment counter
            BRz END_LOOP           ; If counter equals to 0, exit the loop
            LD R0, ASCII_NEWLINE    ; Load the ASCII code of newline character
            OUT                    ; Output newline character
            LD R0, ASCII_SPACE      ; Load the ASCII code of space character
            OUT                    ; Output space character
            LD R0, R2              ; Load the address of "Hello" message
            OUT                    ; Output "Hello" message
            BR LOOP                ; Repeat the loop
END_LOOP    RET                    ; Return from subroutine

; Data section
HELLO_MSG   .STRINGZ "Hello"
ASCII_SPACE .FILL x0020             ; ASCII code for space character
ASCII_NEWLINE .FILL x000A           ; ASCII code for newline character

And here is the LC-3 main program to input N from the keyboard, call the subroutine, and output "Hello" for N times:

; Main program to call PRINT_HELLO subroutine
; Input: None
; Output: None

            .ORIG x3000

            ; Prompt the user to input N
            LEA R0, PROMPT_MSG
            PUTS
            GETC
            OUT
            PUTS

            ; Convert ASCII to decimal
            AND R1, R1, #0
            AND R2, R2, #0
            ADD R2, R2, #-48
            ADD R1, R1, R2
            GETC
            ADD R1, R1, R1
            ADD R1, R1, R1
            ADD R1, R1, R2
            ADD R0, R1, #0

            ; Call PRINT_HELLO subroutine
            JSR PRINT_HELLO

            ; Exit program
            HALT

; Data section
PROMPT_MSG  .STRINGZ "Enter N: "

This program prompts the user to input N, converts the ASCII code to decimal, calls the PRINT_HELLO subroutine with N as the input, and outputs "Hello" for N times.