Messages in this thread | | | Date | Thu, 22 May 2003 11:36:08 -0700 | From | William Lee Irwin III <> | Subject | Re: arch/i386/kernel/mpparse.c warning fixes |
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William Lee Irwin III writes: >> m->mpc_apicid is an 8-bit type; MAX_APICS can be 256. The above fix >> properly compares two integral expressions of equal width.
On Thu, May 22, 2003 at 08:29:41PM +0200, mikpe@csd.uu.se wrote: > In the original "_>_", the 8-bit mpc_apicid is implicitly converted to int > before the comparison, as part of the "integer promotions" in the "usual > arithmetic conversions" (C standard lingo). The same happens in your "_-_<=0". > So what's the benefit of the rewrite?
It removes a warning about comparisons being always true or false by virtue of the limited range of a type.
William Lee Irwin III writes: >> Also, as MAX_APICS-1 is reserved for the broadcast physical APIC ID >> (it's 0xF for serial APIC and 0xFF for xAPIC) the small semantic change >> here is correct.
On Thu, May 22, 2003 at 08:29:41PM +0200, mikpe@csd.uu.se wrote: > No argument there, except that ">=" gets the job done in a cleaner way.
This is actually massively confused anyway. It gets physical APIC ID checks wrong for sparse xAPIC's on mach-default. But that's another issue.
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