Mystery instructions

[jacob navia]

Hi
The GNU assembler supports two instructions for the T-Head risk machines called:

th.ipop
th.ipush

With no arguments. These instructions (they are no macros or aliases) are UNDOCUMENTED in the T-Head instruction manuals that I have, and a google search yields absolutely nothing.

Can anyone here point me to some documentation that describes what these instructions do?

Thanks in advance.