| rax | 101 | get input/output permission | 8 bit |
| rbx | from | from portaddress | 32 bit |
| rcx | num | and to num ports | 32 bit |
| rdx | turn_on | a c++ value = 1 | 8 bit |
| On return | rax |
| 0/errorcode |
| Errorcode | c++ name | Description |
| 9 | EBADF | Bad file number |
| 14 | EFAULT | Bad address |
| 22 | EINVAL | Invalid argument |
| 25 | ENOTTY | Not a typewriter |