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net/ipv6: make use of bitarithm_clzb() in ipv6_addr_match_prefix()

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This commit is contained in:
Benjamin Valentin 2023-05-23 14:37:25 +02:00
parent abe5949cd2
commit d8438c47cf
1 changed files with 8 additions and 17 deletions
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25
sys/net/network_layer/ipv6/addr/ipv6_addr.c
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@ -20,6 +20,7 @@
#include <stdio.h>
#include "fmt.h"
#include "bitarithm.h"
#include "kernel_defines.h"
#include "net/ipv6/addr.h"
@ -52,26 +53,16 @@ uint8_t ipv6_addr_match_prefix(const ipv6_addr_t *a, const ipv6_addr_t *b)
}
for (int i = 0; i < 16; i++) {
uint8_t xor = a->u8[i] ^ b->u8[i];
if (xor) {
/* if bytes aren't equal count matching leading bits */
prefix_len += bitarithm_clzb(xor);
break;
}
else {
/* if bytes are equal add 8 */
if (a->u8[i] == b->u8[i]) {
prefix_len += 8;
}
else {
uint8_t xor = (a->u8[i] ^ b->u8[i]);
/* while bits from byte equal add 1 */
for (int j = 0; j < 8; j++) {
if ((xor & 0x80) == 0) {
prefix_len++;
xor = xor << 1;
}
else {
break;
}
}
break;
}
}
return prefix_len;