On Sat, Nov 28, 2015 at 4:47 PM, Ganesh Ajjanagadde wrote:
> On Sat, Nov 28, 2015 at 4:35 PM, Derek Buitenhuis
> wrote:
>> On 11/28/2015 9:26 PM, Derek Buitenhuis wrote:
>>> Changing all of them sounds fine to me.
>>
>> [21:31] <@ubitux> re: i%4 vs i&3; you should ask him to make sure the
>> com
On Sat, Nov 28, 2015 at 4:35 PM, Derek Buitenhuis
wrote:
> On 11/28/2015 9:26 PM, Derek Buitenhuis wrote:
>> Changing all of them sounds fine to me.
>
> [21:31] <@ubitux> re: i%4 vs i&3; you should ask him to make sure the
> compiler is smart enough regarding the signess of i
No idea, actually G
On 11/28/2015 9:26 PM, Derek Buitenhuis wrote:
> Changing all of them sounds fine to me.
[21:31] <@ubitux> re: i%4 vs i&3; you should ask him to make sure the compiler
is smart enough regarding the signess of i
- Derek
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ffm
On 11/28/2015 9:19 PM, Ganesh Ajjanagadde wrote:
> I actually prefer keeping all at i % 4, since that conveys intent
> better IMHO, and would change uniformly to that. It takes a reader a
> couple of seconds extra to register what i & 3 is doing for no gain in
> C code. No compiler I know of in 201
On Sat, Nov 28, 2015 at 3:29 PM, Derek Buitenhuis
wrote:
> On 11/28/2015 5:03 PM, Ganesh Ajjanagadde wrote:
>> +if (i % 4 == 0)
>
> I doubt it particularly matters in this case, but you can
> avoid a modulo operator here with i & 3, like elsewhere
> in the file. I doubt the compiler is tha
On 11/28/2015 5:03 PM, Ganesh Ajjanagadde wrote:
> +if (i % 4 == 0)
I doubt it particularly matters in this case, but you can
avoid a modulo operator here with i & 3, like elsewhere
in the file. I doubt the compiler is that dumb, though.
Same for other occurrences.
- Derek
__
This further speeds up runtime initialization, with identical generated tables.
Sample benchmark (x86-64, Haswell, GNU/Linux):
old:
34441423 decicycles in mpegaudio_tableinit,8192 runs, 0 skips
new:
10776291 decicycles in mpegaudio_tableinit,8192 runs, 0 skips
Most low hanging
