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)
 
<sourcesyntaxhighlight lang="asm">
MOV AL, 0xC1 ; 0xC1 refers to CCR1
OUT 0x22, AL ; Select Register
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MOV AL, AH ; Load new contents
OUT 0x23, AL ; Write new CCR1 with No-Lock set
</syntaxhighlight>
</source>
[[Category:X86 CPU]]