division... slow?

In a lot of videogame code, whenever a lot of numbers are to be divided by one number, I usually see this:

inv = 1.0 / divisor;
...and then all the numbers * by inv

rather than all the numbers being / by divisor.

I'm guessing, at the CPU level, division is slightly slower and less efficient than multiplication?  I can't really think of any other reason why someone would do this.

If divisor is a constant, and your compiler is not smart enough, this should increase performance. Division is more costly than multiplication. Depending on the processor design, the difference can be very large.

>>2
>If divisor is a constant, and your compiler is not smart enough

That must be some compiler.

its because a computer thinks in base 2, while we do it in base 10. So some simple base 10 decimals are harder to convert as base 2 decimals

>>4
God, just don't even post if you're going to say something this stupid.

>>4
Whut

>>4
It has nothing whatsoever to do with base conversions. Don't be so retarded.