Re: Why is UInt32 << 32 a no-op?
Re: Why is UInt32 << 32 a no-op?
- Subject: Re: Why is UInt32 << 32 a no-op?
- From: "Eric A. Borisch" <email@hidden>
- Date: Tue, 17 Nov 2009 20:09:21 -0600
I was thinking of the situation presented with a 32 bit data value; presumably there would be logic elsewhere to keep the shift value <=32 (64, really)
Any solution will have its own set of caveats; this addresses enabling a 32 bit shift on a 32 bit data value without extra processing (branching) overhead...
On Tue, Nov 17, 2009 at 1:50 PM, Alastair Houghton
<email@hidden> wrote:
On 17 Nov 2009, at 18:49, Eric A. Borisch wrote:
> If you're on a 64-bit platform, this shouldn't have much (if any) of a
> performance hit:
>
> n = (UInt64) n << shift
Though it will still be undefined if shift happens to go higher than 64.
That might seem obvious, but consider the case where shift is calculated somehow; it's pretty easy to end up with it largely unbounded if you aren't careful.
--
Eric A. Borisch
email@hiddenHoward Roark laughed.
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