Re: [PATCH] fbdev: radeon: Remove 'struct timeval' usage

From: Tina Ruchandani
Date: Fri Jun 05 2015 - 03:55:14 EST


>>> + hz = 1000000/delta;
>
> This needs to be on of the do_div family.
>
> Dave.

Hi Dave,
I build-tested the patch for both 32-bit and 64-bit x86. If my
understanding is correct, since the divisor is 64-bit here, the
compiler will do "if (delta > 1000000) hz = 0; else hz =
1000000/(s32)delta" automatically?
In general, is this a good thumb-rule to follow - use do_div if the
dividend is 64-bit, and normal divide operator if only the divisor is
64-bit?

Tina
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