Wednesday, 28 February 2007

Using shift operator for faster division and multiplication

Multiplications

12 * 2 = 12 << 1
12 * 4 = 12 << 2
12 * 8 = 12 << 3
12 * 16 = 12 << 4
12 * 32 = 12 << 5
12 * 64 = 12 << 6
12 * 128 = 12 << 7
12 * 256 = 12 << 8

Divisions

12 / 2 = 12 >> 1
12 / 4 = 12 >> 2
12 / 8 = 12 >> 3
12 / 16 = 12 >> 4
12 / 32 = 12 >> 5
12 / 64 = 12 >> 6
12 / 128 = 12 >> 7
12 / 256 = 12 >> 8

Example


<?php
$a = 12 << 1;
print $a;
?>



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1 comment:

Crescent said...

Hey that was good and basic funda.
Cursorily went through your blogs. You must have real patience to mainatin so many.

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cheers