Re: [lwip-users] lwip_standard_chksum()

[Leon Woestenberg]

Hello Curt,

first look through the code, my brain triggered on something in memory 
that seemed to have survived time despite wear and beer:

> lwip_standard_chksum2(void *dataptr, int len)
> {
>  u8_t *pb = dataptr;
>  u16_t *ps, t = 0;
>  u32_t sum = 0;
>  int odd = ((u32_t)pb & 1);
>
>  /* Get aligned to u16_t */
>  if (odd && len > 0) {
>    ((u8_t *)&t)[1] = *pb++;
>  
This fetches a 16-bit word, possible on a non-16 bit aligned address. 
Some CPU's will puke at this point and stop execution. I wish I could 
name a few CPUs with 100% certainty but I cannot now, though I am sure 
have come across this on some 16 and 32-bit platforms.

What should be done here is fetch a 8-bit number on a 8-bit aligned 
address (which is always the case :-)).

Regards,

Leon.