29 lines
1.1 KiB
C
29 lines
1.1 KiB
C
|
/*---------------------------------------------------------------------------*/
|
||
|
|
#ifdef UIP_ARCH_IPCHKSUM
|
||
|
|
u16_t
|
||
|
|
uip_ipchksum(void)
|
||
|
|
{
|
||
|
|
/* Assumes proper alignement of uip_buf. */
|
||
|
|
u16_t *p = (u16_t *)&uip_buf[UIP_LLH_LEN];
|
||
|
|
register u16_t sum;
|
||
|
|
|
||
|
|
sum = p[0];
|
||
|
|
asmv("add %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[1]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[2]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[3]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[4]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[5]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[6]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[7]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[8]));
|
||
|
|
asmv("addc %[p], %[sum]": [sum] "+r" (sum): [p] "m" (p[9]));
|
||
|
|
|
||
|
|
/* Finally, add the remaining carry bit. */
|
||
|
|
asmv("addc #0, %[sum]": [sum] "+r" (sum));
|
||
|
|
|
||
|
|
/* Return sum in network byte order. */
|
||
|
|
return (sum == 0) ? 0xffff : sum;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
/*---------------------------------------------------------------------------*/
|