thunder wrote:
> Hi
>
> I have a question regarding Fixed point Arithmetic addition.
>
> For example, i have two fixed point numbers:
>
> a = unsigned Q7.8 format (7-bit integer, 8 bit factional).
> b = unsigned Q7.8 format ( " " ).
>
> Now a + b = c, where c is an unsigned Q8.8 result.

Then there is overflow, just as two Q15.0 integers and getting a Q16.0
sum. (Remember the sign bit.)

> Qs: How do I transform c into d, where d is a unsigned Q7.9 result ??

You can't. Count the bits. (Remember the sign bit.)

...

> QS; Can anyone recommend a good book on Fixed Point and Floating point
> arithmetic ?

http://www.digitalsignallabs.com/fp.pdf

Jerry
--
Engineering is the art of making what you want from things you can get.
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