Re: [PATCH v3 next 09/10] lib: mul_u64_u64_div_u64() Optimise the divide code

[Nicolas Pitre]

On Wed, 18 Jun 2025, Nicolas Pitre wrote:

> On Wed, 18 Jun 2025, David Laight wrote:
> 
> > If the low divisor bits are zero an alternative simpler divide
> > can be used (you want to detect it before the left align).
> > I deleted that because it complicates things and probably doesn't
> > happen often enough outside the tests cases.
> 
> Depends. On 32-bit systems that might be worth it. Something like:
> 
> 	if (unlikely(sizeof(long) == 4 && !(u32)d))
> 		return div_u64(n_hi, d >> 32);

Well scratch that. Won't work obviously.


Nicolas