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libretroadmin
f62d495d2d
A CHD was read through one decoded hunk and a thread that decoded one hunk ahead. A game that plays CD audio while it streams data reads the two from different places a sector at a time, so each threw out the other's hunk and aimed the thread away from it, and the hunks were decoded on the emulation thread: a stutter a GDI never shows. Each stream (data tracks, audio tracks) now reads through its own libretro-common vfs_prefetch, whose thread decodes the hunks ahead on an image handle of its own, one window per hunk; sectors are lent from the windows in place, and a read command's Prefetch() sets the data stream's thread going before the first sector is asked for. The core defines HAVE_THREADS where it builds threads, so the prefetcher is not compiled to stubs. tools/chd/chd_streams_test, run from tools/chd/run.sh and now in CI, reads audio and data at once and fails when the reading thread does the decoding.
core
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