Sean Cavanaugh wrote:
Some reference:
C++ simd intrinsic for dot product (requires SSE 4.1, very
modern)
_mm_dp_ps
Good to know, thanks!
C++ simd instrinsic for horizontal add (requires SSE3, also
reasonably modern)
_mm_hadd_ps
Awesome, I see XMM.HADDPS (amoung others) in core.simd now,
thanks again!
If you are on SSE2 (which is the base spec for x64) and also
the minimum CPU target we use at work for commercial game
development, you are stuck doing shuffles and adds for dot
product, which effectively process these operations as scalar).
Ideally one of the sides of the dot product is an array and you
can vectorize the dot product itself (1 vector vs 4 others, or
4 v 4). This is common when setting up shapes like view
frustum culling (point tested against 6-8 extruded planes in an
array)
Thanks for the info.
