On 5 February 2012 07:47, Sean Cavanaugh <WorksOnMyMachine@gmail.com> wrote:

Looks good so far:

it could use float[2] code wherever there is float[3] code (magnitude2 etc)

Yep, I intended to do this. You'll see I added dot2, I just didin't add the others yet :P

Note: this is FAR from complete, I just wanted to get initial opinions before I took it too far.

any/all should have template overloads to let you specificy exactly which channels match, and simple hardcoded ones for the common cases (any1, any2, any3, any4 aka the default 'any')

... I'll look into it again more closely, but I don't think I can bring myself to do this. It's ONLY really possible on SSE. Something so expensive shouldn't be in the base API I don't think.

The only case where this operation is particular common is working with 3d vectors. In my experience (fairly extensive, on many architectures) you will almost always have 0's or 1's in the W anyway, which you can control the mask by choosing greater or greater-equal. With careful consideration, you can achieve this at zero cost, and not providing that API leads you to consider such a construct.

I have implementations of floor/ceil/round(to-even) that work on pre-SSE4 hardware for float and doubles I can give out they are fairly simple, as well as the main transcendentals (pow, exp, log, sin, cos, tan, asin, acos, atan). sinh and cosh being the only major ones I left out.

I did plan to add all of these, just haven't gotten to it. You're more than welcome to contribute your implementations.

I recommend a sincos() functions (and friends) as well. Assuming you implement them as a taylor series, it's more efficient to calculate both at once, and it's rare that you ever call one and not the other.

I just need a place or address to post or mail the code.

Pull request? :)

Or email me: turkeyman at gmail

D should be able to handle names and overloading better, though giving everything unique names was the design choice I made for my library, primarily to make the code searchable and potentially portable to C (aside from the heavy use of const references as argument types).

/agree, but the names I've used are so standardised and expected, that I'm really apprehensive to use different names.

Need more opinions to make a good decision, but currently I'm leaning heavily towards keeping it how it is.

On 2/4/2012 1:57 PM, Manu wrote:

So I've been trying to collate a sensible framework for a standard
cross-platform simd module since Walter added the SIMD stuff.
I'm sure everyone will have a million opinions on this, so I've drawn my
approach up to a point where it properly conveys the intent, and I've
proven the code gen works, and is good. Now I figure I should get
everyone to shoot it down before I commit to the tedious work filling in
all the remaining blanks.

(Note: I've only written code against GDC as yet, since DMD's SSE only
supports x64, and x64 is not supported in Windows)
https://github.com/TurkeyMan/phobos/blob/master/std/simd.d

The code might surprise a lot of people... so I'll give a few words
about the approach.

The key goal here is to provide the lowest level USEFUL set of
functions, all the basic functions that people actually use in their
algorithms, without requiring them to understand the quirks of various
platforms vector hardware.
Different SIMD hardware tends to have very different shuffling,
load/store, component addressing, support for more/less of the primitive
maths operations, etc.
This library, which is the lowest level library I expect programmers
would ever want to use in their apps, should provide that API at the
lowest useful level.

First criticism I expect is for many to insist on a class-style vector
library, which I personally think has no place as a low level, portable API.
Everyone has a different idea of what the perfect vector lib should look
like, and it tends to change significantly with respect to its application.

I feel this flat API is easier to implement, maintain, and understand,
and I expect the most common use of this lib will be in the back end of
peoples own vector/matrix/linear algebra libs that suit their apps.

My key concern is with my function names... should I be worried about
name collisions in such a low level lib? I already shadow a lot of
standard float functions...
I prefer them abbreviated in this (fairly standard) way, keeps lines of
code short and compact. It should be particularly familiar to anyone who
has written shaders and such.

Opinions? Shall I continue as planned?