Quick arithmetic question

[chrisname]

Given a number (call it x), how do you (programatically) find the following multiple of another number (255)? For example, if x is 0, the following multiple of 255 is 255, if x is 700 then the following multiple of 255 is 765.

So, how would you calculate it?

[Moschops]

int product = 255;
while (product < x) 
{
  product = product+255;
}

[chrisname]

Is there any way to do it without using a loop? This needs to be fast since it's part of a 6502 emulator (granted the 6502 was like 4 MHz and can be emulated in Javascript, but, still).

[naraku9333]

Maybe [(x/255) + 1] * 255

[m4ster r0shi]

Or, if you want to also avoid multiplication, x + 255 - x % 255

[chrisname]

Thanks, that looks good. I think I'll use m4ster r0shi's one.