SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
[conv.fpint]/1:
> A prvalue of a floating-point type can be converted to a prvalue of
> an integer type. The conversion truncates; that is, the fractional
> part is discarded. The behavior is undefined if the truncated value
> cannot be represented in the destination type.
Additionally, VCacheEnhance has been added to UVAT_group1. According to YAGCD, this field is always 1.
TVtxDesc also now has separate low and high fields whose hex values correspond with the proper registers, instead of having one 33-bit value. This change was made in a way that should be backwards-compatible.
Keeps all of the floating-point utility functions in their own file to
keep them all together. This also provides a place for other
general-purpose floating-point functions to be added in the future,
which will be necessary when improving the flag-setting within the
interpreter.
Fixes warning:
```
../Source/UnitTests/VideoCommon/VertexLoaderTest.cpp:222:15: error: variable 'f' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
ExpectOut(f * scale);
^
../Source/UnitTests/VideoCommon/VertexLoaderTest.cpp:198:12: note: initialize the variable 'f' to silence this warning
float f, g;
^
= 0.0
../Source/UnitTests/VideoCommon/VertexLoaderTest.cpp:223:15: error: variable 'g' may be uninitialized when used here [-Werror,-Wconditional-uninitialized]
ExpectOut(g * scale);
^
../Source/UnitTests/VideoCommon/VertexLoaderTest.cpp:198:15: note: initialize the variable 'g' to silence this warning
float f, g;
^
= 0.0
```
