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背景
假设数据存放在在unsigned char* m_pData 里面#xff0c;宽和高分别是#xff1a;m_nDataWidth m_nDataHeight 给定缩放比例#xff1a;fXZoom fYZoom#xff0c;返回缩放后的unsigned char* dataZoom 这里采用最简单的缩放算法即#xff1a; 根据比…添加链接描述
背景
假设数据存放在在unsigned char* m_pData 里面宽和高分别是m_nDataWidth m_nDataHeight 给定缩放比例fXZoom fYZoom返回缩放后的unsigned char* dataZoom 这里采用最简单的缩放算法即 根据比例计算原图和缩放后图坐标的对应关系缩放后图坐标*缩放比例 原图坐标
原始代码 未优化
#pragma once
class zoomBlock
{
public:zoomBlock() {};~zoomBlock();void zoomDataSSE128(unsigned char* dataZoom, float fXZoom, float fYZoom);void zoomData(unsigned char* dataZoom, float fXZoom, float fYZoom);void test(float fXZoom 0.5, float fYZoom0.5);void init(int DataWidth, int DataHeight);
private:void computeSrcValues(int* srcValues, size_t size, float zoom, int dataSize);private:unsigned char* m_pData nullptr;float m_fXZoom 1 ;//x轴缩放比例 m_nXZoom1时 不缩放float m_fYZoom 1 ;//y轴缩放比例int m_nDataWidth 0;int m_nDataHeight 0;
};#include zoomBlock.h
#include stdio.h
#include iostream
#includeiomanip
#define SAFE_DELETE_ARRAY(p) { if( (p) ! NULL ) delete[] (p); (p) NULL; }zoomBlock::~zoomBlock()
{SAFE_DELETE_ARRAY(m_pData);
}
void zoomBlock::init(int DataWidth, int DataHeight)
{m_nDataWidth DataWidth;m_nDataHeight DataHeight;m_pData new unsigned char[m_nDataWidth* m_nDataHeight];for (int i 0; i m_nDataWidth * m_nDataHeight; i){m_pData[i] static_castunsigned char(i); // Replace this with your data initialization logic}
}void zoomBlock::zoomData(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;for (size_t row 0; row nZoomDataHeight; row){for (size_t column 0; column nZoomDataWidth; column ){//1int srcx std::min(int(row / fYZoom), m_nDataHeight - 1);int srcy std::min(int(column / fXZoom), m_nDataWidth - 1);//2int srcPos srcx * m_nDataHeight srcy;int desPos row * nZoomDataHeight column;dataZoom[desPos] m_pData[srcPos];}}
}void zoomBlock::test(float fXZoom, float fYZoom)
{init(8,8);std::cout Values in m_pData: std::endl;for (int i 0; i m_nDataWidth * m_nDataHeight; i){std::cout std::setw(4) static_castint(m_pData[i]) ;if ((i 1) % m_nDataWidth 0) { // Adjust the value based on your datastd::cout std::endl;}}unsigned char* dataZoom new unsigned char[fXZoom * m_nDataWidth * fYZoom * m_nDataHeight];zoomData(dataZoom, fXZoom, fYZoom);// Print or inspect the values in m_dataZoomint nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;std::cout Values in m_dataZoom: std::endl;for (int i 0; i nZoomDataHeight * nZoomDataWidth; i){std::cout std::setw(4) static_castint(dataZoom[i]) ;if ((i 1) % nZoomDataWidth 0) { // Adjust the value based on your datastd::cout std::endl;}}SAFE_DELETE_ARRAY(dataZoom);}测试代码
int main()
{zoomBlock zoomBlocktest;zoomBlocktest.test(1.5,1.5);return 0;
}其中函数 ·void zoomBlock::zoomData(unsigned char* dataZoom, float fXZoom, float fYZoom)· 没有使用任何加速优化现在来分析它。
sse128
我们知道sse128可以一次性处理4个int类型所以我们把最后一层for循环改成4个坐标的算法不满4个的单独计算
void zoomBlock::zoomDataSSE128(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;for (size_t row 0; row nZoomDataHeight; row){int remian nZoomDataWidth % 4;for (size_t column 0; column nZoomDataWidth - remian; column 4){//第一个坐标int srcx std::min(int(row / fYZoom), m_nDataHeight - 1);int srcy std::min(int(column / fXZoom), m_nDataWidth - 1);int srcPos srcx * m_nDataHeight srcy;int desPos row * nZoomDataHeight column;dataZoom[desPos] m_pData[srcPos];//第二个坐标int srcx1 std::min(int((row1) / fYZoom), m_nDataHeight - 1);int srcy1 std::min(int((column1) / fXZoom), m_nDataWidth - 1);int srcPos1 srcx1 * m_nDataHeight srcy1;int desPos1 (row1) * nZoomDataHeight column1;dataZoom[desPos1] m_pData[srcPos1];//第3个坐标// 。。。//第4个坐标// 。。。}// Process the remaining elements (if any) without SSEfor (size_t column nZoomDataWidth - remian; column nZoomDataWidth; column){int srcx std::min(int(row / fYZoom), m_nDataHeight - 1);int srcy std::min(int(column / fXZoom), m_nDataWidth - 1);int srcPos srcx * m_nDataHeight srcy;int desPos row * nZoomDataHeight column;dataZoom[desPos] m_pData[srcPos];}}
}上面 一次处理四个坐标的代码要改成sse的代码
在最里层的循环里面每次都要计算 row / fYZoom 和 column / fXZoom这个实际上可以挪出for循环计算一次存到数组里
数据坐标desPos和srcPos 必须放在最内存的循环里
所以我们用calculateSrcIndex函数单独处理 row / fYZoom 和 column / fXZoom希望达到如下效果
void calculateSrcIndex(int* srcValues, int size, float zoom,int max)
{for (int i 0; i size; i){srcValues[i] std::min(int(i/zoom),max);}
}改成sse
void calculateSrcIndex(int* srcValues, int size, float zoom,int max)
{__m128i mmIndex, mmSrcValue, mmMax;mmMax _mm_set1_epi32(max);float zoomReciprocal 1.0f / zoom;int remian size % 4;for (size_t i 0; i size - remian; i 4){mmIndex _mm_set_epi32(i 3, i 2, i 1, i);mmSrcValue _mm_cvtps_epi32(_mm_mul_ps(_mm_cvtepi32_ps(mmIndex), _mm_set1_ps(zoomReciprocal)));// Ensure srcValues are within the valid range [0, max]mmSrcValue _mm_min_epi32(mmSrcValue, mmMax);// Store the result to the srcValues array_mm_storeu_si128(reinterpret_cast__m128i*(srcValues[i]), mmSrcValue);}// Process the remaining elements (if any) without SSEfor (size_t i size - remian; i size; i){srcValues[i] std::min(int(i / zoom), max);}
}解释 这里主要处理int型数据为了使用sse加速要使用__m128i类型来存储4个int
加载int到__m128i __m128i _mm_set1_epi32(int i); 这个指令是使用1个i来设置__m128i将__m128i看做4个32位的部分则每个部分都被赋为i __m128i _mm_set_epi32(int i3, int i2,int i1, int i0); 说明使用4个int(32bits)变量来设置__m128i变量 返回值如果返回值__m128i分为r0,r1,r2,r3返回值规则如下 r0 : i0 r1 : i1 r2 : i2 r3 : i3 __m128i _mm_cvtps_epi32 (__m128 a) Converts packed 32-bit integers in a to packed single-precision (32-bit) floating-point elements.
加载float到__m128
__m128 _mm_set1_ps(float w) 对应于_mm_load1_ps的功能不需要字节对齐需要多条指令。r0 r1 r2 r3 w__m128 _mm_cvtepi32_ps (__m128i a) Converts packed 32-bit integers in a to packed single-precision (32-bit) floating-point elements.
float乘法
__m128 dst _mm_mul_ps (__m128 a, __m128 b) 将a, b中的32位浮点数相乘结果打包给dst
取最小值
__m128i _mm_min_epi32 (__m128i a, __m128i b) Compare packed signed 32-bit integers in a and b, and store packed minimum values in dst. Operation FOR j : 0 to 3 i : j*32 dst[i31:i] : MIN(a[i31:i], b[i31:i]) ENDFOR
所以代码修改为 int* srcX new int[nZoomDataHeight];int* srcY new int[nZoomDataWidth];calculateSrcIndex(srcX, nZoomDataHeight, fXZoom , m_nDataHeight - 1);calculateSrcIndex(srcY, nZoomDataWidth, fYZoom, m_nDataWidth - 1);for (size_t row 0; row nZoomDataHeight; row){int remian nZoomDataWidth % 4;for (size_t column 0; column nZoomDataWidth - remian; column 4){//第一个坐标int srcPos srcX[row] * m_nDataHeight srcY[column];int desPos row * nZoomDataHeight column;dataZoom[desPos] m_pData[srcPos];...}}然后把坐标的计算转为sse
void zoomBlock::zoomDataSSE128(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;int* srcX new int[nZoomDataWidth];int* srcY new int[nZoomDataHeight];calculateSrcIndex(srcX, nZoomDataWidth, fXZoom, m_nDataWidth - 1);calculateSrcIndex(srcY, nZoomDataHeight, fYZoom, m_nDataHeight - 1);for (size_t y 0; y nZoomDataHeight; y){int remian nZoomDataWidth % 4;for (size_t x 0; x nZoomDataWidth - remian; x 4){__m128i mmsrcX _mm_set_epi32(srcX[x 3], srcX[x 2], srcX[x1], srcX[x]);__m128i srcPosIndices _mm_add_epi32(_mm_set1_epi32(srcY[y] * m_nDataWidth),mmsrcX);__m128i desPosIndices _mm_add_epi32(_mm_set1_epi32(y * nZoomDataWidth),_mm_set_epi32(x 3, x 2, x 1, x));dataZoom[desPosIndices.m128i_i32[0]] m_pData[srcPosIndices.m128i_i32[0]];dataZoom[desPosIndices.m128i_i32[1]] m_pData[srcPosIndices.m128i_i32[1]];dataZoom[desPosIndices.m128i_i32[2]] m_pData[srcPosIndices.m128i_i32[2]];dataZoom[desPosIndices.m128i_i32[3]] m_pData[srcPosIndices.m128i_i32[3]];/*cout srcPosIndices: srcPosIndices.m128i_i32[0] , desPosIndices : desPosIndices.m128i_i32[0] endl;cout srcPosIndices: srcPosIndices.m128i_i32[1] , desPosIndices : desPosIndices.m128i_i32[1] endl;cout srcPosIndices: srcPosIndices.m128i_i32[2] , desPosIndices : desPosIndices.m128i_i32[2] endl;cout srcPosIndices: srcPosIndices.m128i_i32[3] , desPosIndices : desPosIndices.m128i_i32[3] endl;*/}// Process the remaining elements (if any) without SSEfor (size_t x nZoomDataWidth - remian; x nZoomDataWidth; x){int srcy std::min(int(y / fYZoom), m_nDataHeight - 1);int srcx std::min(int(x / fXZoom), m_nDataWidth - 1);int srcPos srcy * m_nDataHeight srcx;int desPos y * nZoomDataHeight x;dataZoom[desPos] m_pData[srcPos];}}delete[] srcX;delete[] srcY;
}完整的代码 #pragma once
class zoomBlock
{
public:zoomBlock() {};~zoomBlock();void zoomDataSSE128(unsigned char* dataZoom, float fXZoom, float fYZoom);void zoomData(unsigned char* dataZoom, float fXZoom, float fYZoom);void test(float fXZoom 0.5, float fYZoom0.5);void init(int DataWidth, int DataHeight);
private:inline void calculateSrcIndex(int* srcValues, int size, float zoom, int max);private:unsigned char* m_pData nullptr;float m_fXZoom 1 ;//x轴缩放比例 m_nXZoom1时 不缩放float m_fYZoom 1 ;//y轴缩放比例int m_nDataWidth 0;int m_nDataHeight 0;
};#include zoomBlock.h
#include stdio.h
#include iostream
#includeiomanip
#includeimmintrin.h
using namespace std;
#define SAFE_DELETE_ARRAY(p) { if( (p) ! NULL ) delete[] (p); (p) NULL; }zoomBlock::~zoomBlock()
{SAFE_DELETE_ARRAY(m_pData);
}
void zoomBlock::init(int DataWidth, int DataHeight)
{m_nDataWidth DataWidth;m_nDataHeight DataHeight;m_pData new unsigned char[m_nDataWidth* m_nDataHeight];for (int i 0; i m_nDataWidth * m_nDataHeight; i){m_pData[i] static_castunsigned char(i); // Replace this with your data initialization logic}
}void zoomBlock::zoomData(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;for (size_t y 0; y nZoomDataHeight; y){for (size_t x 0; x nZoomDataWidth; x ){//1int srcy std::min(int(y / fYZoom), m_nDataHeight - 1);int srcx std::min(int(x / fXZoom), m_nDataWidth - 1);//2int srcPos srcy * m_nDataWidth srcx;int desPos y * nZoomDataWidth x;dataZoom[desPos] m_pData[srcPos];}}
}inline void zoomBlock::calculateSrcIndex(int* srcValues, int size, float zoom,int max)
{__m128i mmIndex, mmSrcValue, mmMax;mmMax _mm_set1_epi32(max);float zoomReciprocal 1.0f / zoom;int remian size % 4;for (size_t i 0; i size - remian; i 4){mmIndex _mm_set_epi32(i 3, i 2, i 1, i);mmSrcValue _mm_cvttps_epi32(_mm_mul_ps(_mm_cvtepi32_ps(mmIndex), _mm_set1_ps(zoomReciprocal)));// Ensure srcValues are within the valid range [0, max]mmSrcValue _mm_min_epi32(mmSrcValue, mmMax);// Store the result to the srcValues array_mm_storeu_si128(reinterpret_cast__m128i*(srcValues[i]), mmSrcValue);}// Process the remaining elements (if any) without SSEfor (size_t i size - remian; i size; i){srcValues[i] std::min(int(i / zoom), max);}
}void zoomBlock::zoomDataSSE128(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;int* srcX new int[nZoomDataWidth];int* srcY new int[nZoomDataHeight];calculateSrcIndex(srcX, nZoomDataWidth, fXZoom, m_nDataWidth - 1);calculateSrcIndex(srcY, nZoomDataHeight, fYZoom, m_nDataHeight - 1);for (size_t y 0; y nZoomDataHeight; y){int remian nZoomDataWidth % 4;for (size_t x 0; x nZoomDataWidth - remian; x 4){/*int srcPos srcx * m_nDataHeight srcy;int desPos row * nZoomDataHeight column;*///dataZoom[desPos] m_pData[srcPos];//__m128i mmsrcY _mm_loadu_si128((__m128i*)(srcY));__m128i mmsrcX _mm_set_epi32(srcX[x 3], srcX[x 2], srcX[x1], srcX[x]);__m128i srcPosIndices _mm_add_epi32(_mm_set1_epi32(srcY[y] * m_nDataWidth),mmsrcX);__m128i desPosIndices _mm_add_epi32(_mm_set1_epi32(y * nZoomDataWidth),_mm_set_epi32(x 3, x 2, x 1, x));dataZoom[desPosIndices.m128i_i32[0]] m_pData[srcPosIndices.m128i_i32[0]];dataZoom[desPosIndices.m128i_i32[1]] m_pData[srcPosIndices.m128i_i32[1]];dataZoom[desPosIndices.m128i_i32[2]] m_pData[srcPosIndices.m128i_i32[2]];dataZoom[desPosIndices.m128i_i32[3]] m_pData[srcPosIndices.m128i_i32[3]];/*cout srcPosIndices: srcPosIndices.m128i_i32[0] , desPosIndices : desPosIndices.m128i_i32[0] endl;cout srcPosIndices: srcPosIndices.m128i_i32[1] , desPosIndices : desPosIndices.m128i_i32[1] endl;cout srcPosIndices: srcPosIndices.m128i_i32[2] , desPosIndices : desPosIndices.m128i_i32[2] endl;cout srcPosIndices: srcPosIndices.m128i_i32[3] , desPosIndices : desPosIndices.m128i_i32[3] endl;*/}// Process the remaining elements (if any) without SSEfor (size_t x nZoomDataWidth - remian; x nZoomDataWidth; x){int srcy std::min(int(y / fYZoom), m_nDataHeight - 1);int srcx std::min(int(x / fXZoom), m_nDataWidth - 1);int srcPos srcy * m_nDataHeight srcx;int desPos y * nZoomDataHeight x;dataZoom[desPos] m_pData[srcPos];}}delete[] srcX;delete[] srcY;
}void zoomBlock::test(float fXZoom, float fYZoom)
{init(8,4);std::cout Values in m_pData: std::endl;for (int i 0; i m_nDataWidth * m_nDataHeight; i){std::cout std::setw(4) static_castint(m_pData[i]) ;if ((i 1) % m_nDataWidth 0) { // Adjust the value based on your datastd::cout std::endl;}}int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;unsigned char* dataZoom new unsigned char[nZoomDataWidth * nZoomDataHeight];zoomDataSSE128(dataZoom, fXZoom, fYZoom);//zoomData(dataZoom, fXZoom, fYZoom);// Print or inspect the values in m_dataZoomstd::cout Values in m_dataZoom: std::endl;for (int i 0; i nZoomDataHeight * nZoomDataWidth; i){std::cout std::setw(4) static_castint(dataZoom[i]) ;if ((i 1) % nZoomDataWidth 0) { // Adjust the value based on your datastd::cout std::endl;}}SAFE_DELETE_ARRAY(dataZoom);}int main()
{zoomBlock zoomBlocktest;zoomBlocktest.test(2,1);return 0;
}AVX 256
inline void zoomBlock::calculateSrcIndex256(int* srcValues, int size, float zoom, int max)
{__m256i ymmIndex, ymmSrcValue, ymmMax;ymmMax _mm256_set1_epi32(max);float zoomReciprocal 1.0f / zoom;int remian size % 8;for (size_t i 0; i size - remian; i 8){ymmIndex _mm256_set_epi32(i 7, i 6, i 5, i 4, i 3, i 2, i 1, i);ymmSrcValue _mm256_cvtps_epi32(_mm256_mul_ps(_mm256_cvtepi32_ps(ymmIndex), _mm256_set1_ps(zoomReciprocal)));// Ensure srcValues are within the valid range [0, max]ymmSrcValue _mm256_min_epi32(ymmSrcValue, ymmMax);// Store the result to the srcValues array_mm256_storeu_si256(reinterpret_cast__m256i*(srcValues[i]), ymmSrcValue);}// Process the remaining elements (if any) without AVX2for (size_t i size - remian; i size; i){srcValues[i] std::min(int(i / zoom), max);}
}
void zoomBlock::zoomDataAVX2(unsigned char* dataZoom, float fXZoom, float fYZoom)
{int nZoomDataWidth fXZoom * m_nDataWidth;int nZoomDataHeight fYZoom * m_nDataHeight;int* srcX new int[nZoomDataWidth];int* srcY new int[nZoomDataHeight];calculateSrcIndex(srcX, nZoomDataWidth, fXZoom, m_nDataWidth - 1);calculateSrcIndex(srcY, nZoomDataHeight, fYZoom, m_nDataHeight - 1);for (size_t y 0; y nZoomDataHeight; y){int remian nZoomDataWidth % 8;for (size_t x 0; x nZoomDataWidth - remian; x 8){__m256i ymmSrcX _mm256_set_epi32(srcX[x 7], srcX[x 6], srcX[x 5], srcX[x 4],srcX[x 3], srcX[x 2], srcX[x 1], srcX[x]);__m256i srcPosIndices _mm256_add_epi32(_mm256_set1_epi32(srcY[y] * m_nDataWidth),ymmSrcX);__m256i desPosIndices _mm256_add_epi32(_mm256_set1_epi32(y * nZoomDataWidth),_mm256_set_epi32(x 7, x 6, x 5, x 4, x 3, x 2, x 1, x));dataZoom[desPosIndices.m256i_i32[0]] m_pData[srcPosIndices.m256i_i32[0]];dataZoom[desPosIndices.m256i_i32[1]] m_pData[srcPosIndices.m256i_i32[1]];dataZoom[desPosIndices.m256i_i32[2]] m_pData[srcPosIndices.m256i_i32[2]];dataZoom[desPosIndices.m256i_i32[3]] m_pData[srcPosIndices.m256i_i32[3]];dataZoom[desPosIndices.m256i_i32[4]] m_pData[srcPosIndices.m256i_i32[4]];dataZoom[desPosIndices.m256i_i32[5]] m_pData[srcPosIndices.m256i_i32[5]];dataZoom[desPosIndices.m256i_i32[6]] m_pData[srcPosIndices.m256i_i32[6]];dataZoom[desPosIndices.m256i_i32[7]] m_pData[srcPosIndices.m256i_i32[7]];}// Process the remaining elements (if any) without AVX2for (size_t x nZoomDataWidth - remian; x nZoomDataWidth; x){int srcy std::min(int(y / fYZoom), m_nDataHeight - 1);int srcx std::min(int(x / fXZoom), m_nDataWidth - 1);int srcPos srcy * m_nDataWidth srcx;int desPos y * nZoomDataWidth x;dataZoom[desPos] m_pData[srcPos];}}delete[] srcX;delete[] srcY;
}
