Messages in this thread | | | Date | Mon, 27 Aug 2012 15:58:59 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH 1/2] x86/mce: Pack boolean MCE boot flags into a structure |
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On Mon, Aug 27, 2012 at 04:55:03PM +0530, Naveen N. Rao wrote: > Many MCE boot flags are boolean in nature, but are declared as integers > currently. We can pack these into a bitfield to save some space.
Note that this doesn't necessarily save anything because it needs more code to access, and accesses are more common than the flag
cmpl $0,foo(%rip) 7 bytes testl $1,foo(%rip) 10 bytes bt $0,foo(%rip) 8 bytes
Even worse for writes. The best you can usually do is to use chars on x86.
-Andi
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