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SSSE3: use 16-bit weights. 

Overall, I'm very happy with performance of this code, but not so much
with resulting image. It seems like integer approximations won't do.
I might remove this code altogether, so I didn't update comments.
master
Sebastian Frysztak 8 years ago
parent
72aec87047
commit
95c333cba5
2 changed files with 37 additions and 22 deletions
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  1. 2
      blur.h
  2. 57
      blur_simd.c

2
blur.h
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@ -9,7 +9,7 @@ void blur_impl_naive(uint32_t* src, uint32_t* dst, int width, int height, int sr
void blur_impl_sse2(uint32_t* src, uint32_t* dst, int width, int height, float sigma);
void blur_impl_horizontal_pass_sse2(uint32_t *src, uint32_t *dst, float *kernel, int width, int height);
void blur_impl_ssse3(uint32_t* src, uint32_t* dst, int width, int height, float sigma);
void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int8_t *kernel, int width, int height);
void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int16_t *kernel, int width, int height);
#endif

57
blur_simd.c
View File

@ -23,7 +23,7 @@
// scaling factor for kernel coefficients.
// higher values cause desaturation.
// used in SSSE3 implementation.
#define SCALE_FACTOR 7
#define SCALE_FACTOR 14
void blur_impl_sse2(uint32_t *src, uint32_t *dst, int width, int height, float sigma) {
// prepare kernel
@ -127,7 +127,7 @@ void blur_impl_horizontal_pass_sse2(uint32_t *src, uint32_t *dst, float *kernel,
void blur_impl_ssse3(uint32_t *src, uint32_t *dst, int width, int height, float sigma) {
// prepare kernel
float kernelf[KERNEL_SIZE];
int8_t kernel[KERNEL_SIZE + 1];
int16_t kernel[KERNEL_SIZE + 1];
float coeff = 1.0 / sqrtf(2 * M_PI * sigma * sigma), sum = 0;
for (int i = 0; i < KERNEL_SIZE; i++) {
@ -142,7 +142,7 @@ void blur_impl_ssse3(uint32_t *src, uint32_t *dst, int width, int height, float
// round to nearest integer and convert to int
for (int i = 0; i < KERNEL_SIZE; i++)
kernel[i] = (int8_t)rintf(kernelf[i] * (1 << SCALE_FACTOR));
kernel[i] = (int16_t)lrintf(kernelf[i] * (1 << SCALE_FACTOR));
kernel[KERNEL_SIZE] = 0;
// horizontal pass includes image transposition:
@ -154,8 +154,10 @@ void blur_impl_ssse3(uint32_t *src, uint32_t *dst, int width, int height, float
}
void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int8_t *kernel, int width, int height) {
__m128i _kern = _mm_loadu_si128((__m128i*)kernel);
void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int16_t *kernel, int width, int height) {
__m128i _kern[2];
_kern[0] = _mm_loadu_si128((__m128i*)kernel);
_kern[1] = _mm_loadu_si128((__m128i*)(kernel + 8));
__m128i rgbaIn[REGISTERS_CNT];
for (int row = 0; row < height; row++) {
@ -203,9 +205,10 @@ void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int8_t *kerne
// then we repeat the process for the rest of input pixels,
// call _mm_hadds_epi16 to add adjacent ints and shift right to scale by SCALE_FACTOR.
__m128i rgba, kern;
__m128i rgba, rg, ba, kern;
__m128i zero = _mm_setzero_si128();
__m128i acc = _mm_setzero_si128();
__m128i acc_rg = _mm_setzero_si128();
__m128i acc_ba = _mm_setzero_si128();
const __m128i rgba_shuf_mask = _mm_setr_epi8(0, 4, 8, 12,
1, 5, 9, 13,
@ -213,28 +216,40 @@ void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int8_t *kerne
3, 7, 11, 15);
const __m128i kern_shuf_mask = _mm_setr_epi8(0, 1, 2, 3,
4, 5, 6, 7,
0, 1, 2, 3,
0, 1, 2, 3,
0, 1, 2, 3);
4, 5, 6, 7);
rgba = _mm_shuffle_epi8(rgbaIn[0], rgba_shuf_mask);
kern = _mm_shuffle_epi8(_kern, kern_shuf_mask);
acc = _mm_adds_epi16(acc, _mm_maddubs_epi16(rgba, kern));
rg = _mm_unpacklo_epi8(rgba, zero);
ba = _mm_unpackhi_epi8(rgba, zero);
kern = _mm_shuffle_epi8(_kern[0], kern_shuf_mask);
acc_rg = _mm_add_epi32(acc_rg, _mm_madd_epi16(rg, kern));
acc_ba = _mm_add_epi32(acc_ba, _mm_madd_epi16(ba, kern));
rgba = _mm_shuffle_epi8(rgbaIn[1], rgba_shuf_mask);
kern = _mm_shuffle_epi8(_mm_srli_si128(_kern, 4), kern_shuf_mask);
acc = _mm_adds_epi16(acc, _mm_maddubs_epi16(rgba, kern));
rg = _mm_unpacklo_epi8(rgba, zero);
ba = _mm_unpackhi_epi8(rgba, zero);
kern = _mm_shuffle_epi8(_mm_srli_si128(_kern[0], 8), kern_shuf_mask);
acc_rg = _mm_add_epi32(acc_rg, _mm_madd_epi16(rg, kern));
acc_ba = _mm_add_epi32(acc_ba, _mm_madd_epi16(ba, kern));
rgba = _mm_shuffle_epi8(rgbaIn[2], rgba_shuf_mask);
kern = _mm_shuffle_epi8(_mm_srli_si128(_kern, 8), kern_shuf_mask);
acc = _mm_adds_epi16(acc, _mm_maddubs_epi16(rgba, kern));
rg = _mm_unpacklo_epi8(rgba, zero);
ba = _mm_unpackhi_epi8(rgba, zero);
kern = _mm_shuffle_epi8(_kern[1], kern_shuf_mask);
acc_rg = _mm_add_epi32(acc_rg, _mm_madd_epi16(rg, kern));
acc_ba = _mm_add_epi32(acc_ba, _mm_madd_epi16(ba, kern));
rgba = _mm_shuffle_epi8(rgbaIn[3], rgba_shuf_mask);
kern = _mm_shuffle_epi8(_mm_srli_si128(_kern, 12), kern_shuf_mask);
acc = _mm_adds_epi16(acc, _mm_maddubs_epi16(rgba, kern));
rg = _mm_unpacklo_epi8(rgba, zero);
ba = _mm_unpackhi_epi8(rgba, zero);
kern = _mm_shuffle_epi8(_mm_srli_si128(_kern[1], 8), kern_shuf_mask);
acc_rg = _mm_add_epi32(acc_rg, _mm_madd_epi16(rg, kern));
acc_ba = _mm_add_epi32(acc_ba, _mm_madd_epi16(ba, kern));
acc = _mm_hadds_epi16(acc, zero);
acc = _mm_srai_epi16(acc, SCALE_FACTOR);
rgba = _mm_hadd_epi32(acc_rg, acc_ba);
rgba = _mm_srai_epi32(rgba, SCALE_FACTOR);
// Cairo sets alpha channel to 255
// (or -1, depending how you look at it)
@ -244,7 +259,7 @@ void blur_impl_horizontal_pass_ssse3(uint32_t *src, uint32_t *dst, int8_t *kerne
// lock screen images, so no one will mind if we
// 'correct it' by setting alpha to 255.
*(dst + height * column + row) =
_mm_cvtsi128_si32(_mm_packus_epi16(acc, zero)) | 0xFF000000;
_mm_cvtsi128_si32(_mm_shuffle_epi8(rgba, rgba_shuf_mask));
}
}
}

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