下面这个函数TX_memset4是什么意思了?

#include <iostream>
using namespace std;

void TX_memset4(void *dst, unsigned int val, unsigned int len)
{
unsigned int  __count = (len);
unsigned int __nTimes = (__count + 3) / 4;
unsigned int *__p = (unsigned int*)dst;
unsigned int __val = (val);

if (len == 0)
{
return;
}

switch (__count % 4)
{
case 0:
do
{
*__p++ = __val;
case 3: *__p++ = __val;
case 2: *__p++ = __val;
case 1: *__p++ = __val;
}while(--__nTimes);
}
}

int main(int argc, char *argv[])
{
unsigned int iArr[10];
TX_memset4(iArr, 7, 10);

return 0;
}