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Optimize set_syscall_retval for arm64
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Authored by trasz on Oct 28 2020, 7:44 PM.

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Summary

Optimize set_syscall_retval() for arm64 by predicting the return
value to be zero.

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Repository
R10 FreeBSD src repository
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Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

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trasz requested review of this revision.Oct 28 2020, 7:44 PM

similar to amd64,

if (__predict_true(error == 0)) {
        frame->tf_rax = td->td_retval[0];
        frame->tf_rdx = td->td_retval[1];
        frame->tf_rflags &= ~PSL_C;
        return;
}
emaste added a subscriber: mhorne.

Maybe worth a comment about the microoptimization?

This revision is now accepted and ready to land.Jan 8 2021, 3:37 PM

See also, the analogous commit for riscv: rS367138.

This revision was automatically updated to reflect the committed changes.