sound: Add busy wait to write port status on DSP #88
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…ABILITY_OPTIMIZATION so the design fits.
…eiving DMA commands. Allowed new sounds to play immediately if DMA is paused. Games, such as The Secret to Monkey Island, have a compiled in CT-VOICE driver that communicates to the DSP. When the driver knows a sound is currently playing, it adds an additional step before starting to play the new sound. The driver will poll the write status port (2xCh) until it sees a busy flag, and if it sees it then it sends the pause command first. If the driver never sees a busy status it will eventually timeout polling and skip sending the pause command. Without setting the busy flag a pause command is not sent, the game becomes out of sync with the number of bytes it expects to transfer and locks up. This change was confirmed to fix freezes during The Secret of Monkey Island, Monkey Island 2, and Jill of the Jungle.
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Jan 24, 2022
* Updated project settings OPTIMIZATION_MODE and FITTER_AGGRESSIVE_ROUTABILITY_OPTIMIZATION so the design fits. * Updated the Sound DSP module to look busy while playing sound and receiving DMA commands. Allowed new sounds to play immediately if DMA is paused. Games, such as The Secret to Monkey Island, have a compiled in CT-VOICE driver that communicates to the DSP. When the driver knows a sound is currently playing, it adds an additional step before starting to play the new sound. The driver will poll the write status port (2xCh) until it sees a busy flag, and if it sees it then it sends the pause command first. If the driver never sees a busy status it will eventually timeout polling and skip sending the pause command. Without setting the busy flag a pause command is not sent, the game becomes out of sync with the number of bytes it expects to transfer and locks up. This change was confirmed to fix freezes during The Secret of Monkey Island, Monkey Island 2, and Jill of the Jungle. * Fixed spacing. (cherry picked from commit edbab9d)
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This change addresses some games that freeze because the DSP and game are deadlocked waiting on each other. The focus was to fix the freezing seen in The Secret of Monkey Island, but the change is not specific to it. It will probably improve other games as well.