Mercurial > hg > truffle
comparison src/share/vm/utilities/globalDefinitions.hpp @ 145:f3de1255b035
6603011: RFE: Optimize long division
Summary: Transform long division by constant into multiply
Reviewed-by: never, kvn
| author | rasbold |
|---|---|
| date | Wed, 07 May 2008 08:06:46 -0700 |
| parents | ba764ed4b6f2 |
| children | d1605aabd0a1 12eea04c8b06 |
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| 132:60b728ec77c1 | 145:f3de1255b035 |
|---|---|
| 888 while (p != 0 && p <= (julong)x) { | 888 while (p != 0 && p <= (julong)x) { |
| 889 // p = 2^(i+1) && p <= x (i.e., 2^(i+1) <= x) | 889 // p = 2^(i+1) && p <= x (i.e., 2^(i+1) <= x) |
| 890 i++; p *= 2; | 890 i++; p *= 2; |
| 891 } | 891 } |
| 892 // p = 2^(i+1) && x < p (i.e., 2^i <= x < 2^(i+1)) | 892 // p = 2^(i+1) && x < p (i.e., 2^i <= x < 2^(i+1)) |
| 893 // (if p = 0 then overflow occured and i = 31) | 893 // (if p = 0 then overflow occured and i = 63) |
| 894 return i; | 894 return i; |
| 895 } | 895 } |
| 896 | 896 |
| 897 //* the argument must be exactly a power of 2 | 897 //* the argument must be exactly a power of 2 |
| 898 inline int exact_log2(intptr_t x) { | 898 inline int exact_log2(intptr_t x) { |