[x265] [PATCH Review only] asm: added psy_acEnergy_pp_4x4 in sse4 for psyCost_pp

[Steve Borho]

On 12/17, Divya Manivannan wrote:
> The encoder uses 4x4 block size by testing with these two videos
> NebutaFestival_2560x1600_60_10bit_crop.yuv and 720p50_parkrun_ter.y4m.
> Since there is no similar function definition, I have generated the new
> function definition for 4x4.

It can encode intra 4x4, but the CU in that case is still 8x8 and
psy-energy is always measured at the CU level (for pixels, for residual
it might measure 4x4 shorts).

But why make a function that can only measure one half of the psy-value
when there already exists a function prototype for generating the full
energy score?

I can guess where this is headed, where you write one function that
fills in an array of costs and then call it twice and have the C code
sum the abs(diff) of those costs, but if this is the direction you are
headed then the function prototype needs to be the same for all block
sizes.  Adding conditional paths for different block sizes will make the
function slower, in whole, as will requiring two function calls to make
one energy measurement.

-- 
Steve Borho