On 22 September 2015 at 13:43, Predut, Marius <marius.pre...@intel.com> wrote:
> In the upstream code , 'nr' variable is used intensively in many places for
> things like :
> for (j = 0; j + 2 < count; j += nr ) {
> nr = MIN2( currentsz, count - j );
>
> But first time when it is used it isn't initialized.
> I was unable to find a place (a macro or something) where "nr" is
> initialized.
> I suppose it is done somewhere because if NOT, THIS will be very strange how
> this code works.
> (Every time "nr" became "currentsz" because all the time nr is a big stack
> value, so this is the reason for why code works?)
>
While I cannot quote the C spec, I'm pretty sure that j += nr, will
be executed after nr = MIN2( currentsz, count - j ).
The following simple test confirms it.
int main(void) {
int j, nr;
for (j = 0; j < 10; printf("nr %d\n", nr), j += nr)
nr = 1, printf("hello world %d\n", j);
}
hello world 0
nr 1
hello world 1
...
Cheers,
Emil
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