c – 使用ARM NEON内在函数的cvtColor的SIMD优化

概述我正在使用BGR的SIMD优化来进行灰度转换,相当于 OpenCV’s cvtColor() function.有一个Intel SSE版本的这个功能,我指的是它. (我正在做的是基本上将SSE代码转换为NEON代码.) 我几乎完成了编写代码,可以用g编译它,但是我无法得到正确的输出.有没有人有任何想法可能是什么错误？ 我得到什么(不正确)： 我应该得到什么 这是我的代码： #include <o @H_502_1@我正在使用BGR的SIMD优化来进行灰度转换,相当于 OpenCV’s cvtColor() function.有一个Intel SSE版本的这个功能,我指的是它. (我正在做的是基本上将SSE代码转换为NEON代码.)

我几乎完成了编写代码,可以用g编译它,但是我无法得到正确的输出.有没有人有任何想法可能是什么错误？

我得到什么(不正确)：

我应该得到什么

这是我的代码：

#include <opencv/cv.hpp>#include <opencv/highgui.h>#include <arm_neon.h>//#include <iostream>using namespace std;//using namespace cv;#define int8x16_to_8x8x2(v) ((int8x8x2_t) { vget_low_s8(v),vget_high_s8(v) })voID cvtBGR2GrayNEON(cv::Mat& src,cv::Mat& dest){  const int size = src.size().area()*src.channels();  uchar* s = src.ptr<uchar>(0);  uchar* d = dest.ptr<uchar>(0);  const int8x16_t mask1 = {0,3,6,9,12,15,1,4,7,10,13,2,5,8,11,14};  const int8x16_t smask1 = {6,14,15};  const int8x16_t ssmask1 = {11,10};  const int8x16_t mask2 = {0,13};  const int8x16_t ssmask2 = {0,10};  const int8x16_t bmask1 = {255,255,0};  const int8x16_t bmask2 = {255,0};  const int8x16_t bmask3 = {255,0};  const int8x16_t bmask4 = {255,0};  const int shift = 8;  const int amp = 1<<shift;  const int16_t _R_ = (int16_t)(amP*0.299);  const int16_t _G_ = (int16_t)(amP*0.587);  const int16_t _B_ = (int16_t)(amP*0.114);  const int16x8_t R = vdupq_n_s16(_R_);  const int16x8_t G = vdupq_n_s16(_G_);  const int16x8_t B = vdupq_n_s16(_B_);  const int8x16_t zero = vdupq_n_s8(0);  for(int i = 0; i < size; i += 48)    {      int8x16_t a = vld1q_s8((int8_t *) s + i);      int8x16_t b = vld1q_s8((int8_t *) s + i + 16);      int8x16_t c = vld1q_s8((int8_t *) s + i + 32);      a = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(a),vget_low_s8(mask1)),vtbl2_s8(int8x16_to_8x8x2(a),vget_high_s8(mask1)));      b = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(b),vget_low_s8(mask2)),vtbl2_s8(int8x16_to_8x8x2(b),vget_high_s8(mask2)));      c = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(c),vtbl2_s8(int8x16_to_8x8x2(c),vget_high_s8(mask2)));      //BBBBBB      const int8x16_t aaaa = vbslq_s8(c,vbslq_s8(b,a,bmask1),bmask2);      a = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(a),vget_low_s8(smask1)),vget_high_s8(smask1)));      b = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(b),vget_high_s8(smask1)));      c = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(c),vget_high_s8(smask1)));      //GGGGGG      const int8x16_t bbbb = vbslq_s8(c,bmask3),vget_low_s8(ssmask1)),vget_high_s8(ssmask1)));      c = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(c),vget_high_s8(ssmask1)));      b = vcombine_s8(vtbl2_s8(int8x16_to_8x8x2(b),vget_low_s8(ssmask2)),vget_high_s8(ssmask2)));      //RRRRRR      const int8x16_t cccc = vbslq_s8(c,bmask4);      /*      int8x8x2_t a1 = vzip_s8(vget_high_s8(aaaa),vget_high_s8(zero));      int8x8x2_t a2 = vzip_s8(vget_low_s8(aaaa),vget_low_s8(zero));      */      int8x16_t a1 = aaaa;      int8x16_t a2 = zero;      int8x16x2_t temp1 =  vzipq_s8(a1,a2);      a1 = temp1.val[0];      a2 = temp1.val[1];      int16x8_t aa1 = vmulq_s16((int16x8_t)a2,B);      int16x8_t aa2 = vmulq_s16((int16x8_t)a1,B);      int8x16_t b1 = bbbb;      int8x16_t b2 = zero;      int8x16x2_t temp2 =  vzipq_s8(b1,b2);      b1 = temp2.val[0];      b2 = temp2.val[1];      int16x8_t bb1 = vmulq_s16((int16x8_t)b2,G);      int16x8_t bb2 = vmulq_s16((int16x8_t)b1,G);      int8x16_t c1 = cccc;      int8x16_t c2 = zero;      int8x16x2_t temp3 =  vzipq_s8(c1,c2);      c1 = temp3.val[0];      c2 = temp3.val[1];      int16x8_t cc1 = vmulq_s16((int16x8_t)c2,R);      int16x8_t cc2 = vmulq_s16((int16x8_t)c1,R);      aa1 = vaddq_s16(aa1,bb1);      aa1 = vaddq_s16(aa1,cc1);      aa2 = vaddq_s16(aa2,bb2);      aa2 = vaddq_s16(aa2,cc2);      const int shift1 = 8;      aa1 = vshrq_n_s16(aa1,shift1);      aa2 = vshrq_n_s16(aa2,shift1);      uint8x8_t aaa1 = vqmovun_s16(aa1);      uint8x8_t aaa2 = vqmovun_s16(aa2);      uint8x16_t result = vcombine_u8(aaa1,aaa2);      vst1q_u8((uint8_t *)(d),result);      d+=16;    }    }int main() {  cv::Mat src = cv::imread("Lenna.bmp");  cv::Mat dest(src.rows,src.cols,CV_8UC1);  cvtBGR2GrayNEON(src,dest);  cv::imwrite("grey.jpg",dest);  return 0;}

这是等效的SSE代码(从here)：

voID cvtBGR2GraySSEShort(Mat& src,Mat& dest){    const int size = src.size().area()*src.channels();    uchar* s = src.ptr<uchar>(0);    uchar* d = dest.ptr<uchar>(0);    //data structure    //BGR BGR BGR BGR BGR B    //GR BGR BGR BGR BGR BG    //R BGR BGR BGR BGR BGR    //shuffle to BBBBBBGGGGGRRRRR    const __m128i mask1 = _mm_setr_epi8(0,14);    const __m128i smask1 = _mm_setr_epi8(6,15);    const __m128i ssmask1 = _mm_setr_epi8(11,10);    //shuffle to GGGGGGBBBBBRRRRR    const __m128i mask2 = _mm_setr_epi8(0,13);    //const __m128i smask2 = _mm_setr_epi8(6,15);same as smask1    const __m128i ssmask2 = _mm_setr_epi8(0,10);    //shuffle to RRRRRRGGGGGBBBBB    //__m128i mask3 = _mm_setr_epi8(0,13);//same as mask2    //const __m128i smask3 = _mm_setr_epi8(6,10);//same as smask1    //const __m128i ssmask3 = _mm_setr_epi8(11,10);//same as ssmask1    //blend mask    const __m128i bmask1 = _mm_setr_epi8        (255,0);    const __m128i bmask2 = _mm_setr_epi8        (255,0);    const __m128i bmask3 = _mm_setr_epi8        (255,0);    const __m128i bmask4 = _mm_setr_epi8        (255,0);      const int shift = 8;    const int amp = 1<<shift;    const int _R_=(int)(amP*0.299);    const int _G_=(int)(amP*0.587);    const int _B_=(int)(amP*0.114);    const __m128i R = _mm_set1_epi16(_R_);    const __m128i G = _mm_set1_epi16(_G_);    const __m128i B = _mm_set1_epi16(_B_);    const __m128i zero = _mm_setzero_si128();       for(int i=0;i<size;i+=48)    {        __m128i a = _mm_shuffle_epi8(_mm_load_si128((__m128i*)(s+i)),mask1);        __m128i b = _mm_shuffle_epi8(_mm_load_si128((__m128i*)(s+i+16)),mask2);        __m128i c = _mm_shuffle_epi8(_mm_load_si128((__m128i*)(s+i+32)),mask2);        const __m128i aaaa = _mm_blendv_epi8(c,_mm_blendv_epi8(b,bmask2);        a = _mm_shuffle_epi8(a,smask1);        b = _mm_shuffle_epi8(b,smask1);        c = _mm_shuffle_epi8(c,smask1);        const __m128i bbbb =_mm_blendv_epi8(c,ssmask1);        c = _mm_shuffle_epi8(c,ssmask1);        b = _mm_shuffle_epi8(b,ssmask2);        const __m128i cccc =_mm_blendv_epi8(c,bmask4);        __m128i a1 = _mm_unpackhi_epi8(aaaa,zero);        __m128i a2 = _mm_unpacklo_epi8(aaaa,zero);        a1 = _mm_mullo_epi16(a1,B);        a2 = _mm_mullo_epi16(a2,B);        __m128i b1 = _mm_unpackhi_epi8(bbbb,zero);        __m128i b2 = _mm_unpacklo_epi8(bbbb,zero);        b1 = _mm_mullo_epi16(b1,G);        b2 = _mm_mullo_epi16(b2,G);        __m128i c1 = _mm_unpackhi_epi8(cccc,zero);        __m128i c2 = _mm_unpacklo_epi8(cccc,zero);        c1 = _mm_mullo_epi16(c1,R);        c2 = _mm_mullo_epi16(c2,R);        a1 = _mm_add_epi16(a1,b1);        a1 = _mm_add_epi16(a1,c1);        a2 = _mm_add_epi16(a2,b2);        a2 = _mm_add_epi16(a2,c2);        a1 = _mm_srli_epi16(a1,8);        a2 = _mm_srli_epi16(a2,8);        a = _mm_packus_epi16(a1,a2);        _mm_stream_si128((__m128i*)(d),a);        d+=16;    } }

解决方法 好的,下面是我刚刚写的那个函数的完全优化版本(请注意,如果大小小于32,则此函数只返回)

/* *  Created on: 2014. 7. 27. *      Author: Jake Lee *      Project FANIC - Fastest ARM NEON Implementaion Challenge */// voID fanicCvtBGR2GrayNEON(voID *pDst,voID *pSrc,unsigned int size);// Y = 0.114*B + 0.587*G + 0.299*R    .text    .arm    .global fanicCvtBGR2GrayNEON    pDst    .req    r0    pSrc    .req    r1    size    .req    r2    .align 5    .funcfanicCvtBGR2GrayNEON:    pld     [pSrc]    subs    size,size,#32    pld     [pSrc,#64]    bxmi    lr    pld     [pSrc,#64*2]    vmov.i8     d0,#29    vmov.i8     d1,#150    vmov.i8     d2,#77    .align 51:    vld3.8      {d20,d21,d22},[pSrc]!    vld3.8      {d23,d24,d25},[pSrc]!    vld3.8      {d26,d27,d28},[pSrc]!    vld3.8      {d29,d30,d31},[pSrc]!    vmull.u8    q8,d20,d0    vmlal.u8    q8,d1    vmlal.u8    q8,d22,d2    vmull.u8    q9,d23,d0    vmlal.u8    q9,d1    vmlal.u8    q9,d25,d2    vmull.u8    q10,d26,d0    vmlal.u8    q10,d1    vmlal.u8    q10,d28,d2    vmull.u8    q11,d29,d0    vmlal.u8    q11,d1    vmlal.u8    q11,d31,d2    vrshrn.u16  d24,q8,#8    vrshrn.u16  d25,q9,#8    vrshrn.u16  d26,q10,#8    vrshrn.u16  d27,q11,#8    subs    size,#64*3]    pld     [pSrc,#64*4]    vst1.8      {q12,q13},[pDst]!    bpl     1b    cmp     size,#-32    add     pSrc,pSrc,size    bxle    lr    add     pSrc,lsl #1    add     pDst,pDst,size    b       1b    .endfunc    .end

正如你所看到的,在组装中编写NEON代码比在内在函数中更容易和更短,尽管重度展开.

玩的开心.

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