On 02/24/2016 07:28 AM, Matthias Pfaller wrote:
> On 02/23/2016 09:11 PM, Jeff Epler wrote:
>> Since you are already using cc extensions like ({ ... }), you may prefer
>> to use __COUNTER__ rather than __LINE__.
>>
>>
>> Consider preprocessor input like
>> #define X __LINE__
>> #define Y X,X,X,X
>>
>> Y;
>>
>> #undef X
>> #define X __COUNTER__
>>
>> Y;
>>
>> The first definition of X gives
>> 4,4,4,4; // depending on the line that first Y; is on
>> and the second one gives
>> 0,1,2,3;
>>
>>
>> This can be particularly important if mrs() is used multiple times in another
>> macro, since when the macro is expanded it is all expanded with the same
>> value for __LINE__.
>
> Thank's for the hint. That is indeed alot better than __LINE__. I had
> totally forgoten about __COUNTER__.
It looks like all this is not enough. While this solves my problem, I
thinke there are cases where gcc will still will apply CSE. Consider:
static int
mrsbasepri(void)
{
return(mrs(basepri));
}
When gcc decides to inline mrsbasepri it will again be free to CSE the
mrs instructions :-(. Is it really just me having run into this problem?
How do other people solve the problem that __asm__ without input is
handled like a __attribute((const)) function?
regards, Matthias
--
Matthias Pfaller Software Entwicklung
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