This is a shortcut for the needs descriptor
00000077:03515104_00000000_00000000. It requires blending a single 32-bit
colour value into a 16-bit framebuffer.
It's used when fading out the screen, eg. when a modal requester pops-up.
The PF JIT produces code for this using 24 instructions/pixel. The NEON
implementation requires 2.1 instructions/pixel. Performance hasn't been
benchmarked, but the improvement is quite visible.
This code has only been tested by inspection of the fading effect described
above, when press+holding a finger on the home screen to pop up the
Shortcuts/Widgets/Folders/Wallpaper requester.
Along with the NEON version, a fallback v5TE implementation is also provided.
This ARM version of col32cb16blend is not fully optimised, but is a reasonable
implementation, and better than the version produced by the JIT. It is here as
a fallback, if NEON is not available.
* Add support for UXTB16 to the disassembler
* Add encoding of the UXTB16 instruction to the Pixelflinger JIT.
Introducing the UXTB16 instruction allows removal of some masking code, and is
beneficial from a pipeline point of view - lots of UXTB16 followed by MUL
sequences.
Also, further rescheduling and use of SMULWB brings extra performance
improvements.
* Use UXTB16 in bilinear filtered texturing
Uses UXTB16 to extract channels for SIMD operations, rather than creating and
ANDing with masks. Saves a register and is faster on A8, as UXTB16 result can
feed into first stage of multiply, unlike AND.
Also, used SMULWB rather than SMULBB, which allows removal of MOVs used to
rescale results.
Code has been scheduled for A8 pipeline, specifically aiming to allow
multiplies to issue in pipeline 0, for efficient dual issue operation.
Testing on SpriteMethodTest (http://code.google.com/p/apps-for-android/) gives
8% improvement (12.7 vs. 13.7 fps.)
SMULBB to SMULWB trick could be used in <v6 code path, but this hasn't been
implemented.
when ONE / ONE_MINUS_SRC_ALPHA blending mode was used, the code wasn't saturating the color component.
the reason was that this mode is used for premltiplied alpha blending, however, if used with a non
premultiplied source, the color component would wrap.
unfortunately, this costs 6 extra cycles per pixels, however... "correctness" prevails.
this should not impact the UI since it's using h/w acceleration most of the time it also doesn't
impact games which should be using h/w GL. This change will slow the emulator down a bit.
A better fix would be to banish this qemu tracing stuff from libhardware
and also banish it from non-emulator builds, but this at least gets the
minimal build building again.
