CPU Bugs: Difference between revisions
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To fix this bug, one must write to the cyrix registers and set the NO-LOCK bit in CCR1, which disables all but the most essential bus locks. The downside of this is that read-modify-write atomicity is no longer guaranteed on multiprocessor systems. Source code that should prevent this condition: (untested) |
To fix this bug, one must write to the cyrix registers and set the NO-LOCK bit in CCR1, which disables all but the most essential bus locks. The downside of this is that read-modify-write atomicity is no longer guaranteed on multiprocessor systems. Source code that should prevent this condition: (untested) |
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< |
<syntaxhighlight lang="asm"> |
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MOV AL, 0xC1 ; 0xC1 refers to CCR1 |
MOV AL, 0xC1 ; 0xC1 refers to CCR1 |
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OUT 0x22, AL ; Select Register |
OUT 0x22, AL ; Select Register |
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MOV AL, AH ; Load new contents |
MOV AL, AH ; Load new contents |
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OUT 0x23, AL ; Write new CCR1 with No-Lock set |
OUT 0x23, AL ; Write new CCR1 with No-Lock set |
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</syntaxhighlight> |
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</source> |
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[[Category:X86 CPU]] |
[[Category:X86 CPU]] |
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