ProjectArcade

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# RX4E4Z - Casper's Scare School: Spooky Sports Day
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[OnFrame]
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# Work around a dcache issue by preventing the game from doing something pointless.
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#
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# The game's DVD read function writes 0x87654321 to the entire read buffer and 0x12345678 to the
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# last 4 bytes. It then calls DVDReadAsync() and without waiting for the read to complete at all,
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# it checks if the last 4 bytes are still 0x12345678. If they are, then the game fails.
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#
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# The check always passes on console because DVDReadAsync() -> issueCommand() calls
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# DCInvalidateRange() (dcbi) on the read buffer.
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#
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# Dolphin cannot emulate this without an extremely significant performance hit.
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#
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# .text:800D2E64 lis       r7, game_dvd_read_callback@ha
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# .text:800D2E68 stw       r0, 0(r17) # write 0x12345678 to the end of the buffer
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# .text:800D2E6C mr        r5, read_length # length
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# .text:800D2E70 mr        r6, read_offset # offset
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# .text:800D2E74 addi      r3, this, file.file_info # file_info
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# .text:800D2E78 subi      r4, r4, dvd_read_buf@l # addr
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# .text:800D2E7C addi      r7, r7, game_dvd_read_callback@l # callback
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# .text:800D2E80 li        r8, 2         # unknown
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# .text:800D2E84 bl        DVDReadAsync
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#
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$Fix file reads (dcache bypass)
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0x800d2e68:dword:0x60000000
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[OnFrame_Enabled]
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$Fix file reads (dcache bypass)
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