Mercurial > jdk8-mips64-public > hotspot / file comparison
comparison: src/share/vm/adlc/dict2.cpp
src/share/vm/adlc/dict2.cpp
- changeset 1040
- 98cb887364d3
- parent 997
- 1580954e694c
- child 1063
- 7bb995fbd3c0
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| 1039:ec59443af135 | 1040:98cb887364d3 |
|---|---|
| 273 | 273 |
| 274 //------------------------------Hashing Functions---------------------------- | 274 //------------------------------Hashing Functions---------------------------- |
| 275 // Convert string to hash key. This algorithm implements a universal hash | 275 // Convert string to hash key. This algorithm implements a universal hash |
| 276 // function with the multipliers frozen (ok, so it's not universal). The | 276 // function with the multipliers frozen (ok, so it's not universal). The |
| 277 // multipliers (and allowable characters) are all odd, so the resultant sum | 277 // multipliers (and allowable characters) are all odd, so the resultant sum |
| 278 // is odd - guarenteed not divisible by any power of two, so the hash tables | 278 // is odd - guaranteed not divisible by any power of two, so the hash tables |
| 279 // can be any power of two with good results. Also, I choose multipliers | 279 // can be any power of two with good results. Also, I choose multipliers |
| 280 // that have only 2 bits set (the low is always set to be odd) so | 280 // that have only 2 bits set (the low is always set to be odd) so |
| 281 // multiplication requires only shifts and adds. Characters are required to | 281 // multiplication requires only shifts and adds. Characters are required to |
| 282 // be in the range 0-127 (I double & add 1 to force oddness). Keys are | 282 // be in the range 0-127 (I double & add 1 to force oddness). Keys are |
| 283 // limited to MAXID characters in length. Experimental evidence on 150K of | 283 // limited to MAXID characters in length. Experimental evidence on 150K of |
| 294 assert( k < (MAXID + 1), "Exceeded maximum name length"); | 294 assert( k < (MAXID + 1), "Exceeded maximum name length"); |
| 295 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size | 295 return (int)((sum+xsum[k]) >> 1); // Hash key, un-modulo'd table size |
| 296 } | 296 } |
| 297 | 297 |
| 298 //------------------------------hashptr-------------------------------------- | 298 //------------------------------hashptr-------------------------------------- |
| 299 // Slimey cheap hash function; no guarenteed performance. Better than the | 299 // Slimey cheap hash function; no guaranteed performance. Better than the |
| 300 // default for pointers, especially on MS-DOS machines. | 300 // default for pointers, especially on MS-DOS machines. |
| 301 int hashptr(const void *key) { | 301 int hashptr(const void *key) { |
| 302 #ifdef __TURBOC__ | 302 #ifdef __TURBOC__ |
| 303 return (int)((intptr_t)key >> 16); | 303 return (int)((intptr_t)key >> 16); |
| 304 #else // __TURBOC__ | 304 #else // __TURBOC__ |
| 305 return (int)((intptr_t)key >> 2); | 305 return (int)((intptr_t)key >> 2); |
| 306 #endif | 306 #endif |
| 307 } | 307 } |
| 308 | 308 |
| 309 // Slimey cheap hash function; no guarenteed performance. | 309 // Slimey cheap hash function; no guaranteed performance. |
| 310 int hashkey(const void *key) { | 310 int hashkey(const void *key) { |
| 311 return (int)((intptr_t)key); | 311 return (int)((intptr_t)key); |
| 312 } | 312 } |
| 313 | 313 |
| 314 //------------------------------Key Comparator Functions--------------------- | 314 //------------------------------Key Comparator Functions--------------------- |
