cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hash_func01.h (1321B)

      1/* SPDX-License-Identifier: LGPL-2.1
      2 *
      3 * Based on Paul Hsieh's (LGPG 2.1) hash function
      4 * From: http://www.azillionmonkeys.com/qed/hash.html
      5 */
      6
      7#define get16bits(d) (*((const __u16 *) (d)))
      8
      9static __always_inline
     10__u32 SuperFastHash (const char *data, int len, __u32 initval) {
     11	__u32 hash = initval;
     12	__u32 tmp;
     13	int rem;
     14
     15	if (len <= 0 || data == NULL) return 0;
     16
     17	rem = len & 3;
     18	len >>= 2;
     19
     20	/* Main loop */
     21#pragma clang loop unroll(full)
     22	for (;len > 0; len--) {
     23		hash  += get16bits (data);
     24		tmp    = (get16bits (data+2) << 11) ^ hash;
     25		hash   = (hash << 16) ^ tmp;
     26		data  += 2*sizeof (__u16);
     27		hash  += hash >> 11;
     28	}
     29
     30	/* Handle end cases */
     31	switch (rem) {
     32        case 3: hash += get16bits (data);
     33                hash ^= hash << 16;
     34                hash ^= ((signed char)data[sizeof (__u16)]) << 18;
     35                hash += hash >> 11;
     36                break;
     37        case 2: hash += get16bits (data);
     38                hash ^= hash << 11;
     39                hash += hash >> 17;
     40                break;
     41        case 1: hash += (signed char)*data;
     42                hash ^= hash << 10;
     43                hash += hash >> 1;
     44	}
     45
     46	/* Force "avalanching" of final 127 bits */
     47	hash ^= hash << 3;
     48	hash += hash >> 5;
     49	hash ^= hash << 4;
     50	hash += hash >> 17;
     51	hash ^= hash << 25;
     52	hash += hash >> 6;
     53
     54	return hash;
     55}