Dwayne Reid wrote:


You are right - I wrote in a confusing manner.  I have 2 quantities, where
>a goes increases when b decreases, similar to the wiper on a pot.  In
>effect, I want to find the position of the wiper expressed as a number from
>00 to FF.
>
>One other thing: since a + b is a constant, the sum of the two will also
>fit in 9 bits.

Why not simply multiply a with a constant that make the result = 0xFF00 when a is max, then use only the high byte of the answer?

Multiplying with a constant gives fast short code.

Regards
/Morgan

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