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fast div aproximation

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Alexander 2017-01-23 04:56:37 +03:00
parent cae99973db
commit c76f541dad
1 changed files with 8 additions and 4 deletions
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12
src/libImaging/AlphaComposite.c
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@ -112,8 +112,10 @@ ImagingAlphaComposite(Imaging imDst, Imaging imSrc)
mm_out_a = _mm256_add_epi32(_mm256_mullo_epi16(mm_src_a, vmm_max_alpha), mm_blend);
mm_coef1 = _mm256_mullo_epi32(mm_src_a, vmm_max_alpha2);
// 8 bits
mm_coef1 = _mm256_cvtps_epi32(_mm256_div_ps(_mm256_cvtepi32_ps(mm_coef1),
_mm256_cvtepi32_ps(mm_out_a)));
mm_coef1 = _mm256_cvtps_epi32(
_mm256_mul_ps(_mm256_cvtepi32_ps(mm_coef1),
_mm256_rcp_ps(_mm256_cvtepi32_ps(mm_out_a)))
);
// 8 bits
mm_coef2 = _mm256_sub_epi32(vmm_max_alpha, mm_coef1);
@ -175,8 +177,10 @@ ImagingAlphaComposite(Imaging imDst, Imaging imSrc)
// coef1 = src->a * 255 * 255 / outa
mm_coef1 = _mm_mullo_epi32(mm_src_a, mm_max_alpha2);
// [8] xx xx xx c3 xx xx xx c2 xx xx xx c1 xx xx xx c0
mm_coef1 = _mm_cvtps_epi32(_mm_div_ps(_mm_cvtepi32_ps(mm_coef1),
_mm_cvtepi32_ps(mm_out_a)));
mm_coef1 = _mm_cvtps_epi32(
_mm_mul_ps(_mm_cvtepi32_ps(mm_coef1),
_mm_rcp_ps(_mm_cvtepi32_ps(mm_out_a)))
);
// [8] xx xx xx c3 xx xx xx c2 xx xx xx c1 xx xx xx c0
mm_coef2 = _mm_sub_epi32(mm_max_alpha, mm_coef1);