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AR30 is optimized with 3 techniques 1. vpmulhuw is used to replicate 8 bits to 10 bits. 2. Two channels are processed at a time. R and B, and A and G. 3. vpshufb is used to shift and mask 2 channels of R and B Red Blue With the 8 bit value in the upper bits, vpmulhuw by (1024+4) will produce a 10 bit value in the low 10 bits of each 16 bit value. This is whats wanted for the blue channel. The red needs to be shifted 4 left, so multiply by (1024+4)*16 for red. Alpha Green Alpha and Green are already in the high bits so vpand can zero out the other bits, keeping just 2 upper bits of alpha and 8 bit green. The same multiplier could be used for Green - (1024+4) putting the 10 bit green in the lsb. Alpha would be a simple multiplier to shift it into position. It wants a gap of 10 above the green. Green is 10 bits, so there are 6 bits in the low short. 4 more are needed, so a multiplier of 4 gets the 2 bits into the upper 16 bits, and then a shift of 4 is a multiply of 16, so (4*16) = 64. Then shift the result left 10 to position the A and G channels. Bug: libyuv:751 Test: ARGBToAR30_Opt Change-Id: Ie4f20dce18203bae7b75acb1fd5232db8a8a4f11 Reviewed-on: https://chromium-review.googlesource.com/820046 Commit-Queue: Frank Barchard <fbarchard@chromium.org> Reviewed-by: Cheng Wang <wangcheng@google.com> |
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| .. | ||
| testdata | ||
| basictypes_test.cc | ||
| color_test.cc | ||
| compare_test.cc | ||
| convert_test.cc | ||
| cpu_test.cc | ||
| cpu_thread_test.cc | ||
| math_test.cc | ||
| planar_test.cc | ||
| rotate_argb_test.cc | ||
| rotate_test.cc | ||
| scale_argb_test.cc | ||
| scale_test.cc | ||
| unit_test.cc | ||
| unit_test.h | ||
| video_common_test.cc | ||