[En-Nut-Discussion] NutEnterCritical vs NutEnterCriticalAccess()

[Ole Reinhardt]

Hi Nathan,

even with this solution, the variable update itself would still be
non-atomic (load and store), wouldn't it?

Further this adds a lot of extra code that Uwe wanted to avoid?

Btw:

Uwe, what exactly is you intention here? Do you need to save CPU cycles?
Or do you want to avoid global (or local?) interrupt disabling?

If I understand your basic idea a little better, perhaps I have more
ideas for a solution.

Best regards,

Ole


Am 17.11.2015 15:33, schrieb Nathan Moore:
> How about something like the following for each target cpu?
> 
> #define NutCriticalUpdate( VARIABLE, VALUE)              \
>      do {
>          \
>               size_t sz_ = sizeof(typeof(VARIABLE));            \
>               size_t sza_ = sizeof(sig_atomic_t);                    \
>               typeof(VARIABLE) * VP_ = &(VARIABLE);        \
>               typeof(VALUE) VAL_ = (VALUE);                     \
>               if (sz_ == sza_ && is_alligned(VP_)  {               \
>                      *VP_ = VAL_;
>  \
>               } else if (sz_ < sza) {
>   \
>                    /* special consideration for cpu */               \
>               } else {
>        \
>                    NutEnterCritical();
>  \
>                    *VP_ = VAL_;                                            \
>                    NutExitCritical();
>   \
>               }
>         \
>        } while (0)
> _______________________________________________
> http://lists.egnite.de/mailman/listinfo/en-nut-discussion
> 

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