simpler block mix for murmur3c

add mix-constant-generator code
tweak constants for 3c and 3f

git-svn-id: http://smhasher.googlecode.com/svn/trunk@104 77a7d1d3-4c08-bdc2-d393-d5859734b01a

1 files changed, 42 insertions, 45 deletions

diff --git a/MurmurHash3.cpp b/MurmurHash3.cpp
index 28aa6a0..8334435 100644
--- a/MurmurHash3.cpp
+++ b/MurmurHash3.cpp
@@ -88,54 +88,54 @@ void MurmurHash3_x86_32 ( const void * key, int len,
 } 

 

 //-----------------------------------------------------------------------------

-// This mix is large enough that VC++ refuses to inline it unless we use

-// __forceinline. It's also not all that fast due to register spillage.

+// x86 platforms don't have enough registers to do the c1/c2 mixing step

+// without spilling data onto the stack, so we use inline constants for this

+// block mix.

 

 FORCE_INLINE void bmix32 ( uint32_t & h1, uint32_t & h2,

                            uint32_t & h3, uint32_t & h4, 

                            uint32_t & k1, uint32_t & k2, 

-                           uint32_t & k3, uint32_t & k4, 

-                           uint32_t & c1, uint32_t & c2 )

+                           uint32_t & k3, uint32_t & k4 )

 {

-  k1 *= c1; 

-  k1  = ROTL32(k1,11); 

-  k1 *= c2;

+  k1 *= 0x239b961b; 

+  k1  = ROTL32(k1,15); 

+  k1 *= 0xab0e9789;

+

   h1 ^= k1;

-  h1 += h2;

-  h1 += h3;

-  h1 += h4;

+  h1 = h1*3+0x561ccd1b;

+  h1 = ROTL32(h1,19);

 

-  h1 = ROTL32(h1,17);

+  k2 *= 0x38b34ae5; 

+  k2  = ROTL32(k2,16);

+  k2 *= 0xa1e38b93;

 

-  k2 *= c2; 

-  k2  = ROTL32(k2,11);

-  k2 *= c1;

   h2 ^= k2;

-  h2 += h1;

+  h2 = h2*3+0x0bcaa747;

+  h2 = ROTL32(h2,17);

 

-  h1 = h1*3+0x52dce729;

-  h2 = h2*3+0x38495ab5;

+  k3 *= 0x4b2f1cc5; 

+  k3  = ROTL32(k3,17); 

+  k3 *= 0x8cd62ad3;

 

-  c1 = c1*5+0x7b7d159c;

-  c2 = c2*5+0x6bce6396;

-

-  k3 *= c1; 

-  k3  = ROTL32(k3,11); 

-  k3 *= c2;

   h3 ^= k3;

-  h3 += h1;

+  h3 = h3*3+0x96cd1c35;

+  h3 = ROTL32(h3,15);

+

+  k4 *= 0x561ad8f1; 

+  k4  = ROTL32(k4,18);

+  k4 *= 0xaac75299;

 

-  k4 *= c2; 

-  k4  = ROTL32(k4,11);

-  k4 *= c1;

   h4 ^= k4;

-  h4 += h1;

+  h4 = h4*3+0x32ac3b17;

+  h4 = ROTL32(h4,13);

 

-  h3 = h3*3+0x52dce729;

-  h4 = h4*3+0x38495ab5;

+  h1 += h2;

+  h1 += h3;

+  h1 += h4;

 

-  c1 = c1*5+0x7b7d159c;

-  c2 = c2*5+0x6bce6396;

+  h2 += h1;

+  h3 += h1;

+  h4 += h1;

 }

 

 //----------

@@ -165,22 +165,19 @@ void MurmurHash3_x86_128 ( const void * key, const int len,
   uint32_t h3 = 0xfcba5b2d ^ seed;

   uint32_t h4 = 0x32452e3e ^ seed;

 

-  uint32_t c1 = 0x95543787;

-  uint32_t c2 = 0x2ad7eb25;

-

   //----------

   // body

 

-  const uint32_t * blocks = (const uint32_t *)(data);

+  const uint32_t * blocks = (const uint32_t *)(data + nblocks*16);

 

-  for(int i = 0; i < nblocks; i++)

+  for(int i = -nblocks; i; i++)

   {

     uint32_t k1 = getblock(blocks,i*4+0);

     uint32_t k2 = getblock(blocks,i*4+1);

     uint32_t k3 = getblock(blocks,i*4+2);

     uint32_t k4 = getblock(blocks,i*4+3);

 

-    bmix32(h1,h2,h3,h4, k1,k2,k3,k4, c1,c2);

+    bmix32(h1,h2,h3,h4, k1,k2,k3,k4);

   }

 

   //----------

@@ -213,7 +210,7 @@ void MurmurHash3_x86_128 ( const void * key, const int len,
   case  3: k1 ^= tail[ 2] << 16;

   case  2: k1 ^= tail[ 1] << 8;

   case  1: k1 ^= tail[ 0] << 0;

-           bmix32(h1,h2,h3,h4, k1,k2,k3,k4, c1,c2);

+           bmix32(h1,h2,h3,h4, k1,k2,k3,k4);

   };

 

   //----------

@@ -255,26 +252,26 @@ FORCE_INLINE void bmix64 ( uint64_t & h1, uint64_t & h2,
                            uint64_t & c1, uint64_t & c2 )

 {

   k1 *= c1; 

-  k1  = ROTL64(k1,23); 

+  k1  = ROTL64(k1,29); 

   k1 *= c2;

 

   k2 *= c2; 

-  k2  = ROTL64(k2,23);

+  k2  = ROTL64(k2,33);

   k2 *= c1;

 

-  h1 = ROTL64(h1,17);

+  h1 = ROTL64(h1,27);

   h1 += h2;

   h1 ^= k1;

 

-  h2 = ROTL64(h2,41);

+  h2 = ROTL64(h2,31);

   h2 += h1;

   h2 ^= k2;

 

   h1 = h1*3+0x52dce729;

   h2 = h2*3+0x38495ab5;

 

-  c1 = c1*5+0x7b7d159c;

-  c2 = c2*5+0x6bce6396;

+  c1 = c1*3+0x7b7d159c;

+  c2 = c2*3+0x6bce6396;

 }

 

 //----------