Created
November 10, 2011 00:30
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Sum with bitwise boolean and left shift instructions only
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| int | |
| add (int a, int b) | |
| { | |
| int gen = a & b; // carries | |
| int pro = a ^ b; // sum | |
| gen |= pro & (gen << 1); | |
| pro = pro & (pro << 1); | |
| gen |= pro & (gen << 2); | |
| pro = pro & (pro << 2); | |
| gen |= pro & (gen << 4); | |
| pro = pro & (pro << 4); | |
| gen |= pro & (gen << 8); | |
| pro = pro & (pro << 8); | |
| gen |= pro & (gen <<16); | |
| return a ^ b ^ (gen << 1); | |
| } |
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