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| author | Pokechu22 <Pokechu022@gmail.com> | 2022-07-25 19:30:30 -0700 |
|---|---|---|
| committer | Pokechu22 <Pokechu022@gmail.com> | 2022-07-25 20:35:43 -0700 |
| commit | 1dcccb1f75bf6d1d97167da1b136dfb3df4918ee (patch) | |
| tree | 542e028678aff7e1d3b34b84171e794a48221285 | |
| parent | e44b596f50a87863abe2aa3cda92cf7151bea5c2 (diff) | |
DSPHLE: Add warning to use of MAIL_TERMINATE
| -rw-r--r-- | Source/Core/Core/HW/DSPHLE/UCodes/AESnd.cpp | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/Source/Core/Core/HW/DSPHLE/UCodes/AESnd.cpp b/Source/Core/Core/HW/DSPHLE/UCodes/AESnd.cpp index 902d940bde..122044dda6 100644 --- a/Source/Core/Core/HW/DSPHLE/UCodes/AESnd.cpp +++ b/Source/Core/Core/HW/DSPHLE/UCodes/AESnd.cpp @@ -161,7 +161,30 @@ void AESndUCode::HandleMail(u32 mail) break; case MAIL_TERMINATE: INFO_LOG_FMT(DSPHLE, "AESndUCode - MAIL_TERMINATE: {:08x}", mail); - // This doesn't actually change the state of the system. + if (true) // currently no mainline libogc uCode has this issue fixed + { + // The relevant code looks like this: + // + // lrs $acc1.m,@CMBL + // ... + // cmpi $acc1.m,#0xdead + // jeq task_terminate + // + // The cmpi instruction always sign-extends, so it will compare $acc1 with 0xff'dead'0000. + // However, recv_cmd runs in set16 mode, so the load to $acc1 will produce 0x00'dead'0000. + // This means that the comparison never succeeds, and no mail is sent in response to + // MAIL_TERMINATE. This means that __dsp_donecallback is never called (since that's + // normally called in response to DSP_DONE), so __aesnddspinit is never cleared, so + // AESND_Reset never returns, resulting in a hang. We always send the mail to avoid this + // hang. (It's possible to exit without calling AESND_Reset, so most homebrew probably + // isn't affected by this bug in the first place.) + // + // A fix exists, but has not yet been added to mainline libogc: + // https://github.com/extremscorner/libogc2/commit/38edc9db93232faa612f680c91be1eb4d95dd1c6 + WARN_LOG_FMT(DSPHLE, "AESndUCode - MAIL_TERMINATE is broken in this version of the " + "uCode; this will hang on real hardware or with DSP LLE"); + } + // This doesn't actually change the state of the DSP code. m_mail_handler.PushMail(DSP_DONE, true); break; default: |