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#include <stdio.h>
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#include <stdlib.h>
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#include <ctime>
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#include <arm_neon.h>
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// 定义向量大小
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#define SIZE 1024
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// 原始的向量加法函数
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void vector_add(float* A, float* B, float* C, int size) {
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for (int i = 0; i < size; i++) {
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C[i] = A[i] + B[i];
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}
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}
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// 使用NEON指令优化的向量加法函数
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void vector_add_optimized(float* A, float* B, float* C, int size) {
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int i;
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for (i = 0; i < size - 3; i += 4) {
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// 向量加载，将A和B的4个连续元素加载到float32x4_t类型的向量中
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float32x4_t a_vec = vld1q_f32(&A[i]);
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float32x4_t b_vec = vld1q_f32(&B[i]);
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float32x4_t c_vec = vaddq_f32(a_vec, b_vec);
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// 将结果存储到C中
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vst1q_f32(&C[i], c_vec);
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}
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for (; i < size; i++) {
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C[i] = A[i] + B[i];
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}
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}
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int main() {
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float A[SIZE];
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float B[SIZE];
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float C[SIZE];
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float C_optimized[SIZE];
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// 利用for循环将A和B向量的每个元素随机初始化
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for (int i = 0; i < SIZE; i++) {
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A[i] = (float)(rand() % 100);
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B[i] = (float)(rand() % 100);
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}
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// 测试原始向量加法函数的运行时间
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clock_t start_time_original = clock();
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vector_add(A, B, C, SIZE);
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clock_t end_time_original = clock();
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double elapsed_time_original = (double)(end_time_original - start_time_original) / CLOCKS_PER_SEC;
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clock_t start_time_optimized = clock();
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vector_add_optimized(A, B, C_optimized, SIZE);
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clock_t end_time_optimized = clock();
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double elapsed_time_optimized = (double)(end_time_optimized - start_time_optimized) / CLOCKS_PER_SEC;
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printf("original time: %lf s\n", elapsed_time_original);
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// 输出NEON优化后的向量加法的运行时间
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printf("NEON optimized time: %lf s\n", elapsed_time_optimized);
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return 0;
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} |
