看懂第一个VEC-C 程序

//对数据进行一个滤波的过程#include <vec-c.h>extern uchar* p_in_u8;//调用其他模块的变量->输入数据extern uchar* p_out_u8;//调用其他模块的变量->输出数据void vecc_example(int s32SrcStep, int s32DstStep, uint u32N){uchar32 v0,v1,v2;  //类型为 32个uchar长度的向量 共256bit长ushort16 v3,v_coeff;  //16个ushort长向量ushort j;uint16 vacc0 = (uchar32) 0;  //16个uint长向量用32个uchar长向量来初始化，只初始化了前8X32bitushort coeff[16] = {1,2,1,0,2,4,2,0,1,2,1,0,0,0,0,0};v_coeff = *(ushort16*)coeff;  //用上面的数组来初始化v_coeffunsigned short vprMask;  //掩码for (j = 0; j < u32N; ++j){       /* 将数据拷贝到v0,v1,v2中去，注意宽度和指针回退 */v0 = *(uchar32*)p_in_u8;p_in_u8 += s32SrcStep;v1 = *(uchar32*)p_in_u8;p_in_u8 += s32SrcStep;v2 = *(uchar32*)p_in_u8;p_in_u8 -= s32SrcStep;vacc0 = (uint16) vswmpy5(v0, v0, 0,v_coeff,0);  //v0和v0向量拼起来的数据进行滑窗乘积，核为v_coeffvacc0 = vswmac5(v1, v1, 0,v_coeff,4,vacc0); //滑窗累积v3 = (ushort16) vswmac5(v2, v2, 0,v_coeff,8,vacc0,4); //滑窗累积vst(sat, v3, (uchar16*)p_out_u8, vprMask);//转存p_out_u8+=s32DstStep;}}