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Replace the lame big endian crc with wpaul's standard big endian crc

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algorithm, supplied by wpaul himself.  The lame one has an origin
that's been called into question, so rather than argue about that (one
could make an excellent fair use argument), replace it with better
code since that's what FreeBSD is about.

Submitted by: wpaul[1], Klaus Klein

[1] Bill called this a silly bikeshed.  Maybe his is not incorrect.
This commit is contained in:
Warner Losh 2004-05-19 02:16:46 +00:00
parent eba9b48b10
commit 092d0b6b38
2 changed files with 18 additions and 46 deletions
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32
sys/dev/sk/if_sk.c
View File

@ -745,38 +745,24 @@ sk_xmchash(addr)
return (~crc & ((1 << HASH_BITS) - 1));
}
/* gmchash is just a big endian crc */
static u_int32_t
sk_gmchash(addr)
const uint8_t *addr;
{
u_int32_t crc;
u_int idx, bit;
uint8_t tmpData, data;
uint32_t crc, carry;
int idx, bit;
uint8_t data;
/* Compute CRC for the address value. */
crc = 0xFFFFFFFF; /* initial value */
for (idx = 0; idx < 6; idx++) {
data = *addr++;
/* Change bit order in byte. */
tmpData = data;
for (bit = 0; bit < 8; bit++) {
if (tmpData & 1) {
data |= 1 << (7 - bit);
} else {
data &= ~(1 << (7 - bit));
}
tmpData >>= 1;
}
crc ^= (data << 24);
for (bit = 0; bit < 8; bit++) {
if (crc & 0x80000000) {
crc = (crc << 1) ^ GMAC_POLY;
} else {
crc <<= 1;
}
for (data = *addr++, bit = 0; bit < 8; bit++, data >>= 1) {
carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
crc <<= 1;
if (carry)
crc = (crc ^ GMAC_POLY) | carry;
}
}

32
sys/pci/if_sk.c
View File

@ -745,38 +745,24 @@ sk_xmchash(addr)
return (~crc & ((1 << HASH_BITS) - 1));
}
/* gmchash is just a big endian crc */
static u_int32_t
sk_gmchash(addr)
const uint8_t *addr;
{
u_int32_t crc;
u_int idx, bit;
uint8_t tmpData, data;
uint32_t crc, carry;
int idx, bit;
uint8_t data;
/* Compute CRC for the address value. */
crc = 0xFFFFFFFF; /* initial value */
for (idx = 0; idx < 6; idx++) {
data = *addr++;
/* Change bit order in byte. */
tmpData = data;
for (bit = 0; bit < 8; bit++) {
if (tmpData & 1) {
data |= 1 << (7 - bit);
} else {
data &= ~(1 << (7 - bit));
}
tmpData >>= 1;
}
crc ^= (data << 24);
for (bit = 0; bit < 8; bit++) {
if (crc & 0x80000000) {
crc = (crc << 1) ^ GMAC_POLY;
} else {
crc <<= 1;
}
for (data = *addr++, bit = 0; bit < 8; bit++, data >>= 1) {
carry = ((crc & 0x80000000) ? 1 : 0) ^ (data & 0x01);
crc <<= 1;
if (carry)
crc = (crc ^ GMAC_POLY) | carry;
}
}