//-----------------------------------------------------------------------------
// MurmurHash2, 64-bit versions, by Austin Appleby
// 64-bit hash for 64-bit big endian platforms
// This variant is adapted by Luc Laforets to be incorporated into ISA.

#include "MurmurHash2ISA.h"

#define mmix(h,k) { k *= m; k ^= k >> r; k *= m; h *= m; h ^= k; }

uint64_t MurmurHashISA(const void * key, int len, uint64_t seed)
{
	//const uint64_t m = BIG_CONSTANT(0xc6a4a7935bd1e995);
	const uint64_t m = 0xc6a4a7935bd1e995;
	const int r = 47;
	uint64_t l = len;

	uint64_t h = seed ^ (len * m);

	const uint64_t * data = (const uint64_t *)key;
	const uint64_t * end = data + (len / 8);

	while (data != end)
	{
		uint64_t k = *data++;

		k *= m;
		k ^= k >> r;
		k *= m;

		h ^= k;
		h *= m;
	}

	const unsigned char * data2 = (const unsigned char*)data;
	uint64_t t = 0;

	switch (len & 7)
	{
	case 7: t ^= ((uint64_t)(data2[6])) << 48;
	case 6: t ^= ((uint64_t)(data2[5])) << 40;
	case 5: t ^= ((uint64_t)(data2[4])) << 32;
	case 4: t ^= ((uint64_t)(data2[3])) << 24;
	case 3: t ^= ((uint64_t)(data2[2])) << 16;
	case 2: t ^= ((uint64_t)(data2[1])) << 8;
	case 1: t ^= ((uint64_t)(data2[0]));
		t *= m;
	};

	mmix(h, t);
	mmix(h, l);

	h ^= h >> r;
	h *= m;
	h ^= h >> r;

	return h;
}