Write an LC3 Assembly language subroutine that might be converted to an interrupt handler to accept keyboard input as follows: a buffer is allocated to memory locations x4000 through x40FE. The interrupt handler must accept the next character typed (from the appropriate keyboard register) and store it in the next "empty" location in the buffer. Memory location x40FF is used as a pointer to the next available empty buffer location. If the buffer is full (i.e., if a character has been stored in location x40FE), the interrupt handler must display on the screen: "Character cannot be accepted; input buffer full."