memset的源代码（有人说）

void * memset(void * s, int c, size_t count)
{
void *xs = s;
size_t temp;

if (!count)
return xs;
c &= 0xff;
c |= c << 8;
c |= c << 16;
if ((long) s & 1)
{
char *cs = s;
*cs++ = c;
s = cs;
count--;
}
if (count > 2 && (long) s & 2)
{
short *ss = s;
*ss++ = c;
s = ss;
count -= 2;
}
temp = count >> 2;
if (temp)
{
long *ls = s;
for (; temp; temp--)
*ls++ = c;
s = ls;
}
if (count & 2)
{
short *ss = s;
*ss++ = c;
s = ss;
}
if (count & 1)
{
char *cs = s;
*cs = c;
}
return xs;
}