[Mono-list] Mono.Simd - Flow Control (?)

[Nigel Delaney]

Hi,

 

Thanks for the response, it's always great to hear from the person who wrote
the code in question (and this really does look like a great namespace to,
thanks).  Unfortunately, I am still not sure how to implement your idea.  I
gather I can do the wide compare with this method:

 

public unsafe static Vector2d CompareLessThan (this Vector2d v1, Vector2d
v2)

 

However, I am still not sure how I can extract the byte mask.  I gather from
the source code:  

 

 
<https://github.com/mono/mono/blob/0f2995e95e98e082c7c7039e17175cf2c6a00034/
mcs/class/Mono.Simd/Mono.Simd/VectorOperations.cs>
https://github.com/mono/mono/blob/0f2995e95e98e082c7c7039e17175cf2c6a00034/m
cs/class/Mono.Simd/Mono.Simd/VectorOperations.cs

That the ExtractByteMask method is only available for Vector16sb and
Vector16b and not any of the other vector types.  Does this mean I would
have to cast to one of these types in order to run this method?  I am not
sure what the consequences of this would be.  I think (?) that from the
machines perspective these SSE vector objects are all just 16 bytes that get
loaded into the XMM registers, so I don't know if this cast would have any
overhead, put am worried it wouldn't be any more efficient than just
unpacking the values and comparing them separately.  Any thoughts on whether
I could extract a byte mask directly from the vector2d, or if the cast would
be expected to be faster than just unpacking the Vector2d values and
comparing them separately?

 

Thanks again for the help,

Nigel

 

 

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