You may not use syscall for input or output, because the program would then block on the input. Instead,

use an interrupt$-$driven I$/$O routine to handle all input and output. You must do ALL input and output

through the interrupt$-$driven memory$-$mapped input$/$output services, NOT through syscall. You

may NOT poll for I$/$O$.$ The only syscall you may use for this program is a syscall with code $10$ to end

the program.