{"ast_node_type":"other","tokens":[{"end":240,"kind":"keyword","start":0,"text":"|"}]}
| MIPS         | `$28`/`$gp`                             | Global pointer cannot be used as inputs or outputs.                                                                                                                                 |
| MIPS         | `$26`/`$k0`, `$27`/`$k1`                | OS-reserved registers.                                                                                                                                                              |
| MIPS         | `$ra`                                   | Return address cannot be used as inputs or outputs.                                                                                                                                 |