Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver | Date | Fri, 24 Oct 2014 10:59:30 +0300 |
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Peter Zijlstra <peterz@infradead.org> writes:
>> +/* make negative table index stand for the last table entry */ >> +#define TOPA_ENTRY(t, i) ((i) == -1 ? &(t)->table[(t)->last] : &(t)->table[(i)]) > > code does not match comment; negative would be: i < 0, not i == -1.
Indeed.
> Something like: ({ if (i < 0) i += t->size; t->table[i]; }), might work, > of course that goes bang when: i !e [-size,size)
Table indices and sizes are measured in different units. Using -1 to mean the last is just a small convenience, in the code it would be used explicitly as TOPA_ENTRY(topa, -1).end = 1, for example.
Regards, -- Alex
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