Cast operators missing.

[edanor]

Every specialized vector type should implement a conversion operator.

Unit tests are needed to make sure all operators are correct.

[edanor]

Added empty ITOF and UTOF to float classes as well as some unit tests. Actual code is still missing.

While ITOF/UTOF construction will be desired mode of use, these operations should be provided as part of the interface.

Inverse conversion, that is FTOI/FTOU might not be possible as part of signed/unsigned classes because of delayed definition of float types.

[edanor]

Make sure that all cast operators are declared properly.

[edanor]

Cast operators should be placed in specialization class files:

• UTOI/ITOU in integer specializations
• ITOF/FTOI/UTOF/FTOU in float specializations

[edanor]

Cast operators cannot be implemented as part of the interface, because they are dependent on currently not defined data types. Each plugin now defines UMESimdCastOperators<plugin>.h file which is a placeholder for specialized cast operators.

Added cast operators for: SCALAR, AVX, AVX2 and KNC. Support still missing for AVX512.

[edanor]

All cast operators are in place and ready for specialization.

[edanor]

Cast operators should be defined for all vector types as part of following types:

Base type casts (no vector length change, no precision change):

Unsigned vectors:
UTOI - cast unsigned vector to signed integer vector
UTOF - cast unsigned vector to float vector

Signed vectors:
ITOU - cast signed vector to unsigned vector ITOF - cast signed vector to float vector

Float vectors: FTOU - cast float vector to unsigned vector FTOI - cast float vector to signed vector

Example: SIMDVec4_32i will convert into SIMDVec4_32u (ITOU) or SIMDVec4_32f (ITOF)

Vector length altering casts: PACK - assemble vector using two half-length vectors
PACKLO - insert half-length vector into lower half of the vector
PACKHI - insert half-length vector into upper half of the vector

UNPACK - extract upper and lower halves of the vector into half-length vectors
UNPACKLO - extract lower half of the vector into a half-length vector
UNPACKHI - extract higher half of the vector into a half-length vector

Example: SIMDVec4_32f will unpack into 2 SIMDVec2_32f vectors.

Precision altering casts:
DEGRADE - change rank of all scalar elements into lower (e.g. SIMDVec4_64u will be converted to SIMDVec4_32u)
PROMOTE - change rank of all scalar elements into higher (e.g. SIMDVec4_16i will be converted to SIMDVec4_16i)

Status:
- for base type casts there are unit tests already, and casts are implemented
- for vector altering casts, there are no unit tests, but casts are implemented
- for precision altering casts there are no unit tests nor implementation.

These three classes of casts are a preliminary step for defining all type conversions, e.g. SIMD4_64f to SIMD16_8u.