| ??? 08/22/08 14:47 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#157666 - Strength reduction Responding to: ???'s previous message |
Simple math. The average of n samples is sum(a1,a2,...an) / n.
But 256 = 2^8, i.e binary 100000000 (eight zeroes). So when n is a factor of 2 (2, 4, 8, 16, ...) you can shift the sum right one or more steps instead of performing the divide. Replacing a division by a factor of 2 with a shift right is called strength-reduction, and is a common method used by compilers to allow the cheapest possible assembler instructions to be used. |
| Topic | Author | Date |
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| Strength reduction | 01/01/70 00:00 | |
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Yes, sounds waayyy better... | 01/01/70 00:00 |