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    fa0f7522
    coroutine/arm64: Skip saving/restoring x30 twice and use `autiasp` · fa0f7522
    Yuta Saito authored 
    We don't need to save/restore x30 twice, and we can just use `ret`,
which uses x30 as return address register instead of explicit `ret <reg>`
instruction. This also allows us to use `autiasp` instead of `autia1716`
and we can skip setting SP/LR to x16/x17.

Also the size of register save area is shrunk by 16 bytes due to the
removal of extra x30 save/restore.
    fa0f7522
    coroutine/arm64: Skip saving/restoring x30 twice and use `autiasp`
    Yuta Saito authored 
    We don't need to save/restore x30 twice, and we can just use `ret`,
which uses x30 as return address register instead of explicit `ret <reg>`
instruction. This also allows us to use `autiasp` instead of `autia1716`
and we can skip setting SP/LR to x16/x17.

Also the size of register save area is shrunk by 16 bytes due to the
removal of extra x30 save/restore.