Hi there
Have anyone tried to convert the MurmurHash3 to a optimized BASM version? This could really be a nice BASM challenge.
Code snippet from MurmurHash3.cpp by Austin Appleby:
void MurmurHash3_x86_32 ( const void * key, int len, uint32_t seed, void * out ) { const uint8_t * data = (const uint8_t*)key; const int nblocks = len / 4;
uint32_t h1 = seed;
uint32_t c1 = 0xcc9e2d51; uint32_t c2 = 0x1b873593;
//---------- // body
const uint32_t * blocks = (const uint32_t *)(data + nblocks*4);
for(int i = -nblocks; i; i++) { uint32_t k1 = getblock(blocks,i);
k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2;
h1 ^= k1; h1 = ROTL32(h1,13); h1 = h1*5+0xe6546b64; }
//---------- // tail
const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
uint32_t k1 = 0;
switch(len & 3) { case 3: k1 ^= tail[2] << 16; case 2: k1 ^= tail[1] << 8; case 1: k1 ^= tail[0]; k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1; };
//---------- // finalization
h1 ^= len;
h1 = fmix(h1);
*(uint32_t*)out = h1; }
inline uint32_t rotl32 ( uint32_t x, int8_t r ) { return (x << r) | (x >> (32 - r)); }
FORCE_INLINE uint32_t getblock ( const uint32_t * p, int i ) { return p[i]; }
-Atle