Use SIMD for the graphics compositor code

[taisel]

Of note, it looks like that particular block of code can be rewritten to use SIMD.

Specifically:

• SIMD.Int32x4.and() for isolating flags.
• SIMD.Int32x4.greaterThanOrEqual() for comparing flags.
• SIMD.Int32x4.lessThan() for comparing flags.
• SIMD.Int32x4.select() for selecting which pixels win "priority" based on prior SIMD comparison ops.
• SIMD.Int32x4.load() to load from the backing store used by the renderers prior to compositing.
• SIMD.Int32x4.store() to store into the line buffer.
• SIMD.Int32x4.splat() to generate some bitmasks that the SIMD AND ops will use.

Which means we can process up to 4 pixels at once in parallel, in the usual loop of 240 pixels per line.

No reason to nuke legacy non-SIMD based code, as there will be a test before the functions are built to see if SIMD is supported or not, and will patch in the according legacy path if not supported. Albeit, the legacy code needs a good cleanup, since it's illegible as it is JS that codegens more JS.

[taisel]

Need to figure out how to manage the color effects though to play well with SIMD based code.

[taisel]

Need to figure out how to manage the color effects though to play well with SIMD based code.

[taisel]

For users with browsers that support SharedArrayBuffer, this will not affect performance, as the graphics is done offthread for you, and IIRC IodineGBA is CPU thread bound.

This will help browsers that manage to support SIMD before SharedArrayBuffer for running IodineGBA faster...

[taisel]

For users with browsers that support SharedArrayBuffer, this will not affect performance, as the graphics is done offthread for you, and IIRC IodineGBA is CPU thread bound.

This will help browsers that manage to support SIMD before SharedArrayBuffer for running IodineGBA faster...

[taisel]

Apparently we added it to color blending ops first for a completely different use: 938ecd2

[taisel]

Apparently we added it to color blending ops first for a completely different use: 938ecd2

[taisel]

7723a0c

[taisel]

7723a0c

[taisel]

Probably should move the color effects pass out as a separate loop, and quick-store the lower/upper pixel values into a different buffer.

[taisel]

Probably should move the color effects pass out as a separate loop, and quick-store the lower/upper pixel values into a different buffer.

[taisel]

c79bdd9

[taisel]

c79bdd9

[taisel]

92b4946

[taisel]

92b4946