New Member
I want to do the following maths

result = b0 / b1 * 1000

b0 or b1 can be any value between 0 and 255 (except b0 = 0) and I only need the integer part of the result.


b0 = 143, b1 = 215 =>

143 / 215 * 1000 = 665.115

So I want 665.

Since I've not been playing with picaxes too long I find the maths a little confusing.

Any thoughs?


As you've already discovered. The result of maths will always be an integer rounded down. So, for the equation you've shown, do the multiplication first.


Don't forget that RESULT needs to be a word variable.
If b0 is larger than 65, an overflow can occur.
To avoid that, it is possible to split the 1000. eg
RESULT=b0*100/b1*10 (strict left to right operations)

I'm sure somebody will be able to give a fully optimised version.
In fact, I can already 'see' that RESULT=b0*200/b1*5 would be much better.
Last edited:

Jeremy Leach

Senior Member
and RESULT=b0*250/b1*4 a little bit better (pushing the multiplication up as high to the possible ceiling of 65535 - beyond which there will be oveflow - as we can go).


New Member
Thanks guys, that was the last part of the jigsaw in my first pic axe project :)

I've finally got a working system but it's a bit late in the day to post a description, I'll try and find a few mins tomorrow.

Thanks again.


Michael 2727

Senior Member
This may be a good topic to cover in the
Code Snippets section.
Also WORD splitting High byte, Low byte etc.
Including things like math function order/direction
and other things that may trip people up.


New Member
Yeah, good idea. I would have appreciated that. I did a quick search and found a few bits and pieces but a specific post about common maths techniques would go a long way.

Again, thanks for the help.