code: function end () {
            console.log('\n=== REG DUMP ===\n' + cpu.regdump().join('\n'))
            if (options.memDump) console.log('\n\n=== MEM DUMP ===\n' + cpu.memdump(0, 65535).join('\n'))
            process.exit() // workaround for stdin event listener hanging
          }
docs: Called when the LC-2 program has finished running