how is the do loop in the switch code

[parag_paul]

void duff(register char *to, register char *from, register int
count)
{
register int n=(count+7)/8;
switch(count%8){
case 0: do{ *to++ = *from++;
case 7: *to++ = *from++;
case 6: *to++ = *from++;
case 5: *to++ = *from++;
case 4: *to++ = *from++;
case 3: *to++ = *from++;
case 2: *to++ = *from++;
case 1: *to++ = *from++;
}while( --n >0);
}
}

 

[Eric Sosman]

void duff(register char *to, register char *from, register int
count)
{
register int n=(count+7)/8;
switch(count%8){
case 0: do{ *to++ = *from++;
case 7: *to++ = *from++;
case 6: *to++ = *from++;
case 5: *to++ = *from++;
case 4: *to++ = *from++;
case 3: *to++ = *from++;
case 2: *to++ = *from++;
case 1: *to++ = *from++;
}while( --n >0);
}
}

Do you have a question?

Incidentally, despite the suggestive name given to
the function this is not Duff's Device. Also, there's a
better way to accomplish what this code does: call
memcpy (or perhaps memmove) instead.