tree 124dfa2120f05682eb75e564295510958796443c
parent 6a41bc1a39a52b613cd45b204afac168d05f3db1
author Nathaniel Wesley Filardo <wes.filardo@scisemi.com> 1729821300 +0000
committer Nathaniel Wesley Filardo <VP331RHQ115POU58JFRLKB7OPA0L18E3@cmx.ietfng.org> 1732228104 +0000

switcher: avoid a 2nd read of mtdc on error path

When in .Lskip_compartment_call, t0 is spare, in that it will be
overwritten by one of...
- us, in a few instructions (the zeroAllRegistersExcept), or
- zeroAllRegistersExcept in .Ltherad_exit, via
  .Lset_mcause_and_exit_thread, or
- the exception path (.Lforce_unwind via .Lhandle_error_in_switcher)
  bringing us back here, one TrustedFrame further up.

We can use it instead of tp for a temporary value, avoiding the need to
reload mtdc.