| rax | 97 | set the scheduling priority | 8 bit |
| rbx | which | who's priority is set | 8 bit |
| 0 = PRIO_PROCESS (process) | |||
| 1 = PRIO_PGRP (group) | |||
| 2 = PRIO_USER (user) | |||
| rcx | who | Identifier of which (0=this) | 16 bit |
| rdx | prio | priority -20 (most) to 20 (less) | 16 bit |
| On return | rax |
| 0/errorcode |
| Errorcode | c++ name | Description |
| 1 | EPERM | Operation not permitted |
| 3 | ESRCH | No such process |
| 13 | EACCES | Permission denied |
| 22 | EINVAL | Invalid argument |